Exposure to these ethers have been associated with thyroid issues.
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Watch "four ethers" above, and read our profile on serpentwithfeet here.
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It's still quite hard to buy physical goods using bitcoins or ethers.
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The total market capitalization of ethers currently available is now $100 billion.
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Cuban said the team would take bitcoin or ethers and possibly others.
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Finding the truth requires new ideas, and it requires luminiferous ethers to disprove.
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And yet, ethers only represent around 13 percent of all cryptocurrencies out there.
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But over the past seven days, ethers have been trading up 40 percent.
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So where are all the bitcoins and ethers raised in the ICO stored?
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Blockchain is surfing on the hype surrounding bitcoins, ethers, litecoins and initial coins offering.
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Ethereum tokens (ethers) have reached $1,000 on multiple major exchanges for the first time ever.
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The article also misstated the acronym for polybrominated diphenyl ethers, widely used in fire retardants.
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Ether prices are a bit correlated to bitcoin prices as many people trade bitcoins against Ethers.
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In 2009 PBDEs (Polybrominated Diphenyl Ethers) were added to the list, which now comprises 26 chemicals.
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And starting today, Blockchain users will also be able to create Ethereum wallets and hold ethers.
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The company has partnered with ShapeShift — Blockchain users can exchange bitcoins for ethers and vice versa.
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At some point, the total market capitalization of all ethers currently in circulation was above $36 billion.
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If you want to buy bitcoins or ethers, Blockchain has partnered with exchanges to build seamless integrations.
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Yet you can't just throw a toy like this out into the ethers without some consideration of design.
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Around the early 2000s, OPEs begun replacing an older class of fire retardants called polybrominated diphenyl ethers (PBDEs).
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So it means that you can decide to buy ethers with spare change and weekly payments for instance.
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Eventually, researchers homed in on another possibility: a class of flame retardants known as polybrominated diphenyl ethers (PBDEs).
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The chemicals – known as PBDEs, or polybrominated diphenyl ethers - can be used to make clothing or upholstery fire-resistant.
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Polybrominated diphenyl ethers These chemicals are used as flame retardants, chemicals that can slow the speed of a flame.
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First, if you want to short cryptocurrencies without cashing out, you can convert your bitcoins or ethers to USDC.
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You'll then gradually receive ethers on this address — Qarnot doesn't receive any coin, you keep 260 percent of your cryptocurrencies.
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The abstractions representing Ms. Peavy here suggest brightly colored embryos or sleek flying saucers drifting among amniotic fluids or intergalactic ethers.
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Your specter should be someone who briefly floated into your life from the ethers of online dating before disappearing without a trace.
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Many investors have been funneling ethers to exchange them into new tokens that represent a stake in a company or a project.
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The QC1 features two AMD GPUs (Sapphire Nitro+ Radeon RX580 with 8GB of VRAM) and is designed to mine Ethers by default.
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When the team looked for pollutants in the captured amphipods, they found that polybrominated diphenyl ethers were indeed present, but at moderate concentrations.
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AROUND 1936 three neurologists at Harvard Medical School raided the medicine cabinet, filling their boots with morphine, barbiturates, ethers and even cobra venom.
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At the very heart of it is "four ethers," a song that creeps and marches along like Billie Holiday backed by an orchestra.
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And you'll also find people who'll tell you that bitcoins and ethers are worth nothing, and that all of 2017 has been a crazy dream.
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In particular, the report is saying that Chinese citizens won't be able to use exchanges to buy bitcoins, ethers and more using Chinese yuan, and vice versa.
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Research on the toxicity of flame retardants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) led to their phase out of consumer products and appliances.
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Correction (February 22nd 2018): In the original version of this article we wrote that "morphine, barbiturates, ethers and even cobra venom" had been injected into (apparently) willing volunteers.
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And when downloading content from Safari you'll get an actual download manager instead of just downloading into the ethers of iOS and praying you find whatever you downloaded.
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No team was more victimized by the stupid, stupid forces of the universe lifting Paul Pierce's hefty ass into the ethers of creation than the New York Knicks.
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According to a release from the university, the POPs found included polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), which are known to be used as electrical insulators and flame retardants.
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Like the Ethers, the Aeons are built around custom planar magnetic drivers and offered in a choice of a carbon fiber closed-back design or a mesh-covered open-back option.
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Non-fungible tokens or NFTs are cryptographic tokens which are unique, contrary to fungible tokens (think ethers or bitcoins) which are all exactly alike and interchangeable (for technical details, go here).
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There isn't a directory that lists which products have these ethers, but consumers may still be able to reduce exposure by looking for products that advertise themselves as free of flame retardant.
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Also on the Beatdown, the welterweight champ ethers George Zimmerman for threatening Jay-Z over his Trayvon Martin docuseries ... and shows love to Floyd Mayweather and Diddy for considering big career moves.
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Polybrominated Diphenyl Ethers (PBDEs) were used to treat polyurethane foam, hard plastics, textiles, glues and wire insulation, among other products, until 2006 in the U.S. They were banned a few years ealier in Europe.
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WARREN ethers Delaney: "I don't understand why anybody goes to all the trouble of running for president of the United States to talk about what we really can't do and shouldn't fight for." pic.twitter.
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Since putting his first demo ("four ethers," of course) on Soundcloud a few years back, he's collaborated with Björk, been endorsed by Ty Dolla $ign, and opened for Florence and the Machine and Perfume Genius.
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We love Serpentwithfeet because his voice sounds like it was seasoned, marinated, and baked within the golden gates of heaven, which is why we included his track "Four Ethers" on Noisey's 100 best songs of 2016.
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You can hear it using any old pair of headphones, but the Ethers 250s and Audeze's LCD-24zs are the only headphones that always make the hair on the back of my neck stand up when listening.
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The study, published Tuesday in the journal Molecular and Cellular Endocrinology, looked at the four chemicals known to impact the brain of a developing child most: lead, mercury, pesticides, and polybrominated diphenyl ethers (otherwise known as flame retardants).
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The flame retardant chemicals called Polybrominated Diphenyl Ethers, or PBDEs, were used to treat polyurethane foam, hard plastics, textiles, glues and wire insulation, among other products, until 2006 in the U.S. They were banned a few years earlier in Europe.
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In "Four Ethers," a track off his debut EP Blisters, he sings "Baby, it's cool with me that you like to lie, 'cause I see the depression filling up your eyes," his silken voice rising over thunderous drums and sweeping, straight-to-the-heart strings.
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These chemicals include bisphenol A (BPA), which lines food cans made of tin; phthalates, which are used when manufacturing cosmetics and plastic food containers; polybrominated diphenyl ethers (PBDEs) found in the flame retardants added to furniture and packaging; and pesticides such as chlorpyrifos and organophosphates.
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During their biennial reviews, the group routinely tests samples for a suite of contaminants: polychlorinated biphenyls (PCBs); polybrominated diphenyl ethers (PBDEs), which are flame retardants; polycyclic aromatic hydrocarbons (PAHs), which are chemicals resulting from the combustion of fossils fuels; chlorinated pesticides, including dichlorodiphenyltrichloroethane (DDT) compounds; and six metals: lead, copper, zinc, mercury, arsenic and cadmium.
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Its URL started redirecting to Complex's general style section, and a vague note was provided to interested media outlets: After a considerable number of meetings and an arduous process of deliberation, and given the current climate of digital media #menswear, we have decided that, after four years of pummeling the internet with the most fire 'fits, biggest ethers, skin-melting roasts, and having yanked the souls of the fuccbois out of their lifeless bodies, the future of the the [sic] best menswear site ever conceived in the long and sordid history of the internet is ¯\_(ツ)_/¯ Complex failed to monetize the Four Pins website, but the Four Pins Twitter account was a hit all along.
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Similarly, they undergo inverse demand Diels-Alder reactions. 352px The reactivity of enol ethers is highly dependent on the presence of substituents alpha to oxygen. The vinyl ethers are susceptible to polymerization to give polyvinyl ethers. Some vinyl ethers also find some use as inhalation anesthetics.
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Acetals (α-alkoxy ethers R–CH(–OR)–O–R) are another class of ethers with characteristic properties.
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Akin to enamines, enol ethers are electron-rich alkenes by virtue of the electron- donation from the heteroatom via pi-bonding. Enol ethers have oxonium ion character. By virtue of their bonding situation, enol ethers display distinctive reactivity. In comparison with simple alkenes, enol ethers exhibit enhanced susceptibility to attack by electrophiles such as Bronsted acids.
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Both E-series glycol ethers and P-series glycol ethers can be used as intermediates that undergo further chemical reactions, producing glycol diethers and glycol ether acetates. P-series glycol ethers are marketed as having lower toxicity than the E-series. Most glycol ethers are water-soluble, biodegradable and only a few are considered toxic. One study suggests that occupational exposure to glycol ethers is related to low motile sperm count, a finding disputed by the chemical industry.
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Silyl enol ethers react as nucleophiles in many reactions resulting in alkylation, e.g. Mukaiyama aldol addition and Michael reactions. Reactions of silylenol ethers.
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Although ethers resist hydrolysis, they are cleaved by hydrobromic acid and hydroiodic acid. Hydrogen chloride cleaves ethers only slowly. Methyl ethers typically afford methyl halides: :ROCH3 \+ HBr → CH3Br + ROH These reactions proceed via onium intermediates, i.e. [RO(H)CH3]+Br−. Some ethers undergo rapid cleavage with boron tribromide (even aluminium chloride is used in some cases) to give the alkyl bromide.
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Examples can be found in the Nicolaou taxol total synthesis. tert-Butyldimethylsilyl chloride reacts with alcohols in the presence of base to give tert-butyldimethylsilyl ethers: :(Me3C)Me2SiCl + ROH → (Me3C)Me2SiOR + HCl These silyl ethers hydrolyze much more slowly than the trimethylsilyl ethers.
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Although enol ethers can be considered the ether of the corresponding enolates, they are not prepared by alkylation of enolates. Some enol ethers are prepared from saturated ethers by elimination reactions. Ethyl vinyl ether is a potent anesthetic. Alternatively, vinyl ethers can be prepared from alcohols by Iridium-catalyzed transesterification of vinyl esters, especially the widely available vinyl acetate: :ROH + CH2=CHOAc → ROCH=CH2 \+ HOAc Vinyl ethers can be prepared by reaction of ethyne and alcohols in presence of a base.
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Ethers can be prepared by numerous routes. In general alkyl ethers form more readily than aryl ethers, with the later species often requiring metal catalysts. The synthesis of diethyl ether by a reaction between ethanol and sulfuric acid has been known since the 13th century.
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"Stereoselective preparation of E vinyl zirconium derivatives from E or Z enol ethers." The Journal of organic chemistry 65.21 (2000): 7218-7220. Marek's group Halogen exchange method The Marek group have further investigated using zirconium catalyst on E or Z vinyl ethers, which selective for E-vinyl ethers.
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H2SiF6 is a specialized reagent in organic synthesis for cleaving Si–O bonds of silyl ethers. It is more reactive for this purpose than HF. It reacts faster with t-butyldimethysilyl (TBDMS) ethers than triisopropylsilyl (TIPS) ethers. Hexafluorosilicic acid and the salts are used as wood preservation agents.
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Demethylation typically refers to cleavage of ethers, especially aryl ethers, although there are some exceptions, for instance cf. "desipramine". Aryl methyl ethers are pervasive in lignin and many derived compounds. The demethylation of these materials has been the subject of much effort. The reaction typically requires harsh conditions or harsh reagents.
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The second of Nobel Prizes in Chemistry involving crown ethers was awarded for the design and synthesis of molecular machines. Many of these "machines" incorporate crown ethers as essential design components.Pedersen shared the 1987 Nobel Prize in Chemistry for the discovery of the synthetic routes to, and binding properties of, crown ethers.
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The structure of a typical enol ether group Enamines are chemically related to enol ethers. In organic chemistry an enol ether is an alkene with an alkoxy substituent. The general structure is R2C=CR-OR where R = H, alkyl or aryl. A common subfamily of enol ethers are vinyl ethers, with the formula ROCH=CH2.
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Ethers produce slightly more intense molecular ion peaks compared to the corresponding alcohols or alkanes. There are two common cleavage modes. α-cleavage and C-O bond cleavage. Fragmentation modes of aliphatic ethers Aromatic ethers can generate the C6H5O+ ion by loss of the alkyl group rather than H; this can expel CO as in the phenolic degradation.
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Structure of the polymeric diethyl ether peroxide The C-O bonds that comprise simple ethers are strong. They are unreactive toward all but the strongest bases. Although generally of low chemical reactivity, they are more reactive than alkanes. Specialized ethers such as epoxides, ketals, and acetals are unrepresentative classes of ethers and are discussed in separate articles.
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Union Carbide also registered "Cellosolve" as a trademark for "ETHYL SILICATES FOR USE AS BINDERS IN INVESTMENT CASTINGS AND IN ZINC-RICH PRIMERS" (Reg. Number 1019768, September 9, 1975), but let it expire The first one was ethyl cellosolve (ethylene glycol monoethyl ether), with the name now generic for glycol ethers. Glycol ethers are either "e-series" or "p-series" glycol ethers, depending on whether they are made from ethylene oxide or propylene oxide, respectively. Typically, e-series glycol ethers are found in pharmaceuticals, sunscreens, cosmetics, inks, dyes and water-based paints, while p-series glycol ethers are used in degreasers, cleaners, aerosol paints and adhesives.
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Ethers also coordinate to the Mg(II) center in Grignard reagents.
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They are removed by neutral (but toxic) mercuric chloride, to which most other ethers are stable. As a result, the selective deprotection of polyfunctional molecules becomes possible using MTM ethers as the protective groups for their hydroxyl groups.
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In terms of their physical properties they resemble ethers, but are less volatile, higher melting, and less hydrophilic. These properties follow from the polarizability of the divalent sulfur center, which is greater than that for oxygen in ethers.
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Hydroalkoxylation is a chemical reaction that combines alcohols with alkenes or alkynes. The process affords ethers. The reaction converts alkenes to dialkyl or aryl-alkyl ethers: :R'OH + RCH=CH2 → R'OCH(R)-CH3 Similarly, akynes are converted to vinyl ethers: :R'OH + RC≡CH → R'OC(R)=CH2 As shown, the reaction follows the Markovnikov rule. The process exhibits good atom-economy in the sense that no byproducts are produced.
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Cyclic ethers are readily generated by this approach. Elimination reactions compete with dehydration of the alcohol: : R–CH2–CH2(OH) → R–CH=CH2 \+ H2O The dehydration route often requires conditions incompatible with delicate molecules. Several milder methods exist to produce ethers.
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The dehydration of alcohols affords ethers: : 2 R–OH → R–O–R + H2O at high temperature center This direct nucleophilic substitution reaction requires elevated temperatures (about 125 °C). The reaction is catalyzed by acids, usually sulfuric acid. The method is effective for generating symmetrical ethers, but not unsymmetrical ethers, since either OH can be protonated, which would give a mixture of products. Diethyl ether is produced from ethanol by this method.
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They have the general formula R–O–R′, where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.
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IUPAC rules are often not followed for simple ethers. The trivial names for simple ethers (i.e., those with none or few other functional groups) are a composite of the two substituents followed by "ether". For example, ethyl methyl ether (CH3OC2H5), diphenylether (C6H5OC6H5).
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The Williamson reaction is of broad scope, is widely used in both laboratory and industrial synthesis, and remains the simplest and most popular method of preparing ethers. Both symmetrical and asymmetrical ethers are easily prepared. The intramolecular reaction of halohydrins in particular, gives epoxides. In the case of asymmetrical ethers there are two possibilities for the choice of reactants, and one is usually preferable either on the basis of availability or reactivity.
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The reaction is catalyzed by bases and also by transition metal complexes.Alonso, F., Beletskaya, I. P., Yus, M., "Transition-Metal-Catalyzed Addition of Heteroatom-Hydrogen Bonds to Alkynes", Chemical Reviews 2004, volume 104, 3079. Usually symmetrical ethers are prepared by dehydration of alcohols and unsymmetrical ethers by the Williamson ether synthesis from alkyl halides and alkali metal alkoxides.Wilhelm Heitmann, Günther Strehlke, Dieter Mayer "Ethers, Aliphatic" Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim.
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The majority of other methanogens have C30 hydrocarbons and a mixture of C20 and C40 ethers.
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However, secondary and tertiary alcohols give a substantial amount of alkenes and ethers as side products.
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As for other organic compounds, very common ethers acquired names before rules for nomenclature were formalized. Diethyl ether is simply called "ether", but was once called sweet oil of vitriol. Methyl phenyl ether is anisole, because it was originally found in aniseed. The aromatic ethers include furans.
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Glycol ethers are a group of solvents based on alkyl ethers of ethylene glycol or propylene glycol commonly used in paints and cleaners. These solvents typically have a higher boiling point, together with the favorable solvent properties of lower-molecular weight ethers and alcohols. The word "Cellosolve" was registered in 1924 as a United States trademark by Carbide & Carbon Chemicals Corp. (later named Union Carbide Corp.) for "Solvents for Gums, Resins, Cellulose Esters, and the Like".
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Long-chain polysulfides undergo nucleophilic attack on electrophilic sites of carbonates, resulting in the irreversible formation of by-products as ethanol, methanol, ethylene glycol and thiocarbonates. In LiS batteries are conventionally employed cylic ethers (as DOL) or short-chain ethers (as DME) as well as the family of glycol ethers, including DEGDME and TEGDME. One common electrolyte is 1M LiTFSI in DOL:DME 1:1 vol. with1%w/w di LiNO3 as additive for lithium surface passivation.
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Depending on the substituents, some ethers can be cloven with a variety of reagents, e.g. strong base.
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Silver bromate can be used as an oxidant for the transformation of tetrahydropyranyl ethers to carbonyl compounds.
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Trimethylsilyl enol ethers can be prepared from ketones in presence of a strong base and trimethylsilyl chloride or a weak base and trimethylsilyl triflate. Alternatively, enolate salts react with silyl electrophiles. A rather exotic way to generate silyl enol ethers is via the Brook rearrangement of appropriate substrates.
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Citing earlier work on the dissolution of potassium in 16-crown-4, he realized that the cyclic polyethers represented a new class of complexing agents that were capable of binding alkali metal cations. He proceeded to report systematic studies of the synthesis and binding properties of crown ethers in a seminal series of papers. The fields of organic synthesis, phase transfer catalysts, and other emerging disciplines benefited from the discovery of crown ethers. Pedersen particularly popularized the dibenzo crown ethers.
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Polybrominated Diphenyl Ethers in House Dust and Clothes Dryer Lint. Environmental Science & Technology 39(4), 925-931, 2005.
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Important enol ethers include the reagent 3,4-dihydropyran and the monomers methyl vinyl ether and ethyl vinyl ether.
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5-MeO-MiPT is a Class A drug in the United Kingdom as are most ethers of ring-hydroxy tryptamines.
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These include compounds found in lacquer, paint remover, celluloid, gasoline, and cleaning fluids, especially ethers, alcohols, and other volatile compounds.
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Unlike other alkyl ethers, dimethyl ether resists autoxidation. Dimethyl ether is also relatively non-toxic, although it is highly flammable.
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The Boord olefin synthesis is an organic reaction forming alkenes from ethers carrying a halogen atom 2 carbons removed from the oxygen atom (β-halo-ethers) using a metal such as magnesium or zinc. The reaction, discovered by Cecil E. Boord in 1930 The synthesis of beta-bromo-alkyl ethers and their use in further synthesis Lloyd C. Swallen and Cecil E. Boord J. Am. Chem. Soc.; 1930; 52(2) pp 651 - 660; is a classic named reaction with high yields and broad scope.Advanced Organic Chemistry, 4th Edition, Jerry March, 1992.
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General structure of a silyl ether Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R1R2R3Si−O−R4 where R4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. Since R1R2R3 can be combinations of differing groups which can be varied in order to provide a number of silyl ethers, this group of chemical compounds provides a wide spectrum of selectivity for protecting group chemistry.
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A triol is a chemical compound containing three hydroxyl groups (−OH functional groups),Alcohols, Ethers, Thiols and Chirality. such as glycerol.
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Ethers feature C–O–C linkage defined by a bond angle of about 110° and C–O distances of about 140 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.
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18-crown-6 coordinating a potassium ion Crown ethers are cyclic chemical compounds that consist of a ring containing several ether groups. The most common crown ethers are cyclic oligomers of ethylene oxide, the repeating unit being ethyleneoxy, i.e., –CH2CH2O–. Important members of this series are the tetramer (n = 4), the pentamer (n = 5), and the hexamer (n = 6).
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In organic synthesis, PPTS is used as a weakly acidic catalyst, providing an organic soluble source of pyridinium (C5H5NH+) ions. For example, PPTS is used to deprotect silyl ethers or tetrahydropyranyl ethers when a substrate is unstable to stronger acid catalysts. It is also a commonly used catalyst for the preparation of acetals and ketals from aldehydes and ketones.
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Polyvinylmethylether. Polyvinyl ethers are a class of organic polymers derived from vinyl ethers. Common monomers include methyl vinyl ether and ethyl vinyl ether, the polymer having the formula [CH2CH(OR)]n (R = methyl, ethyl). Commercial interest has also focused on polymers derived from ethyl, isobutyl, octadecyl substituents in place of methyl. Like other vinyl polymers, the polymers exhibit tacticity.
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Oxygen and carbon dioxide are also incompatible with MeLi. Methyllithium is usually not prepared, but purchased as a solution in various ethers.
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Important reactions are listed below.Wilhelm Heitmann, Günther Strehlke, Dieter Mayer "Ethers, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2002.
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This reactivity is similar to the tendency of ethers with alpha hydrogen atoms to form peroxides. Reaction with chlorine produces alpha-chloroethers.
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BCl3 is used as a reagent in the synthesis of organic compounds. Like the corresponding bromide, it cleaves C-O bonds in ethers.
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These alkynes react in the annulation reaction to form resorcinol monosilyl ethers which can be de-protected under mild reaction conditions. Base-promoted dehydrohalogenation of (Z)-2-halovinyl ethers to form alkoxyacetylenes is one of the most well established routes of alkyne synthesis (Scheme 10).Danheiser, R.L., Nishida, A., Savariar, S., Trova, M. P. “Trialkylsiloxyalkynes: Synthesis and Aromatic Annulation Reactions. Tetrahedron Lett.
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Oxygen is more electronegative than carbon, thus the hydrogens alpha to ethers are more acidic than in simple hydrocarbons. They are far less acidic than hydrogens alpha to carbonyl groups (such as in ketones or aldehydes), however. Ethers can be symmetrical of the type ROR or unsymmetrical of the type ROR'. Examples of the former are diethyl ether, dimethyl ether, dipropyl ether etc.
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21- and 18-membered diazacrown ether derivatives exhibit excellent calcium and magnesium selectivities and are widely used in ion-selective electrodes. Some or all of the oxygen atoms in crown ethers can be replaced by nitrogens to form cryptands. A well-known tetrazacrown is cyclen in which there are no oxygens. Lariat crown ethers have sidearms that can augment complexation of cation.
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Dipropyl ether is the symmetrical ether of two n-propyl groups. It is a colorless, flammable liquid with a sweet odor typical of ethers.
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Burghoff, B. (2009). “Solvent Impregnated Resins (SIRs) for the Recovery of Low Concentration Ethers and Phenols from Water.” Dissertation, Technische Universiteit Eindhoven, 153 pages, .
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282 (1990); Vol. 64, p.118 (1986) Article. In the Saegusa–Ito oxidation, certain silyl enol ethers are oxidized to enones with palladium(II) acetate.
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Ether cleavage refers to chemical substitution reactions that lead to the cleavage of ethers. Due to the high chemical stability of ethers, the cleavage of the C-O bond is uncommon in the absence of specialized reagents or under extreme conditions. In organic chemistry, ether cleavage is an acid catalyzed nucleophilic substitution reaction. Depending on the specific ether, cleavage can follow either SN1 or SN2 mechanisms.
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PMB ethers are far more susceptible to oxidation than benzyl ethers since they are more electron-rich. The selective deprotection of PMB ethers can be achieved through the use of bis-(2-(2',4'-difluorophenyl)-5-trifluoromethylpyridine)-(4,4'-ditertbutylbipyridine)iridium(III) hexafluorophosphate (Ir[dF(CF3)ppy]2(dtbbpy)PF6) and a mild stoichiometric oxidant such as bromotrichloromethane, BrCCl3. The photoexcited iridium catalyst is reducing enough to fragment the bromotrichloromethane to form a trichloromethyl radical, bromide anion, and the Ir(IV) complex. The electron- poor fluorinated ligands makes the iridium complex oxidising enough to accept an electron from an electron-rich arene such as a PMB ether.
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Additionally, radical probe experiments with 5-hexenyl and cyclopropyl enol ethers did not give any rearranged products.Differding, E.; Rüegg, G. M. Tetrahedron Lett. 1991, 32, 3815.
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With ethers and alcohols the true initiator is the chlorinated product. Polymer with molar mass of 160,000 g/mole and polydispersity index 1.02 can be obtained.
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By changing the reagent in the second step of the reaction, the Kowalski ester homologation can also be used for the preparation of silyl ynol ethers.
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Silanols are generally synthesized by hydrolysis of halosilanes, alkoxysilanes, or aminosilanes. Chlorosilanes are the most common reactants: :R3Si-Cl + H2O → R3Si-OH + HCl The hydrolysis of fluorosilanes requires more forcing reagents, i.e. alkali. The alkoxysilanes (silyl ethers) of the type R3Si(OR') are slow to hydrolyze. Compared to the silyl ethers, silyl acetates are faster to hydrolyze, with the advantage that the released acetic acid is less aggressive.
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Ester or oxy-acid ethers. > Ethers of the third type. > > Many mineral and organic acids containing oxygen combine with an alcohol > upon elimination of water to [form] neutral, volatile ether compounds, which > one can view as coupled compounds of alcohol and acid-water, or, according > to the theory of radicals, as salts in which an acid is bonded with an > ether. probably as a contraction of the German Essigäther, "acetic ether".
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The simplest of methoxy compounds are methanol and dimethyl ether. Other methoxy ethers include anisole and vanillin. Many alkoxides contain methoxy groups, e.g. tetramethyl orthosilicate and titanium methoxide.
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Like some other ethers, dioxane combines with atmospheric oxygen upon prolonged exposure to air to form potentially explosive peroxides. Distillation of dioxanes concentrates these peroxides, increasing the danger.
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2-Bromoethyl ether (or Bis(2-bromoethyl) ether) is an organobromine compound that is also an ether. It is used in the manufacture of pharmaceuticals and crown ethers.
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Halogenation of silyl enol ethers gives haloketones. Acyloins form upon organic oxidation with an electrophilic source of oxygen such as an oxaziridine or mCPBA.Organic Syntheses, Coll. Vol. 7, p.
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Many alkenes do not polymerize in the presence of Ziegler–Natta or Kaminsky catalysts. This problem applies to polar olefins such as vinyl chloride, vinyl ethers, and acrylate esters.
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Ethers like diethyl ether and tetrahydrofuran (THF) can form highly explosive organic peroxides upon exposure to oxygen and light. THF is normally more likely to form such peroxides than diethyl ether. One of the most susceptible solvents is diisopropyl ether, but all ethers are considered to be potential peroxide sources. The heteroatom (oxygen) stabilizes the formation of a free radical which is formed by the abstraction of a hydrogen atom by another free radical.
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Methanol is the precursor to most simple methylamines, methyl halides, and methyl ethers. Methyl esters are produced from methanol, including the transesterification of fats and production of biodiesel via transesterification.
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Hexahydroxy benzene forms esters such as the hexaacetate (-O(CO)CH3)6 (melting point 220 °C) and ethers like hexa-tert-butoxybenzene (-OC(CH3)3)6 (melting point 223 °C).
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As per Chile's Ley de drogas, aka Ley 20000, all esters and ethers of PCP are illegal. As 3-MeO-PCP is an ether of PCP, it is thus illegal.
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Further radical modes of reactivity include radical substitutions on weak C-H bonds to form α‐azido ethers, benzal acetals, and aldehydes, and the conversion of aldehydes to acyl azides.
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I have no child of my own. Possibly, the crown ethers will serve, in a small way, to mark my footprint on earth” and Izatt believing this too shares Pedersen's message.
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As is typical of ethers, dipropyl ether may slowly form explosive organic peroxides over long periods in storage. Antioxidants such as butylated hydroxytoluene are often added to ethers to prevent this process. Due to the shock and light sensitive nature of organic peroxides, dipropyl ether should never be boiled or evaporated to dryness. This concentrates peroxides that may be present, which can then detonate unexpectedly destroying the vessel in which they have deposited or igniting nearby flammable liquids.
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Decabromodiphenyl ether (also known as decaBDE, deca-BDE, DBDE, deca, decabromodiphenyl oxide, DBDPO, or bis(pentabromophenyl) ether) is a brominated flame retardant which belongs to the group of polybrominated diphenyl ethers (PBDEs).
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This reagent is useful for the conversion of esters into vinyl ethers. The Tebbe reagent Cp2TiCl(CH2)Al(CH3)2, arises by the action of 2 equivalents Al(CH3)3 on Cp2TiCl2.
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Vinyl ethers (CH2=CHOR, R = methyl, ethyl, isobutyl, benzyl) are very reactive vinyl monomers. Studied systems are based on I2/HI and on zinc halides zinc chloride, zinc bromide and zinc iodide.
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Ethers serve as Lewis bases and Bronsted bases. Strong acids protonate the oxygen to give "oxonium ions". For instance, diethyl ether forms a complex with boron trifluoride, i.e. diethyl etherate (BF3·OEt2).
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Common silyl ethers are: trimethylsilyl (TMS), tert- butyldiphenylsilyl (TBDPS), tert-butyldimethylsilyl (TBS/TBDMS) and triisopropylsilyl (TIPS). They are particularly useful because they can be installed and removed very selectively under mild conditions.
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The toxicity of vinyl ethers has been heavily investigated because divinyl ether has been used as an anesthetic. The acute LD50 for methyl vinyl ether is greater than 4 g/kg (rats, oral).
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Cyclic silyl enol ethers undergo regiocontrolled one-carbon ring contractions.(a) Wohl, R. Helv. Chim. Acta 1973, 56, 1826. (b) Xu, Y. Xu, G.; Zhu, G.; Jia, Y.; Huang, Q. J. Fluorine Chem.
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Salts of barium, lead, silver, and others are also known. Croconic acid also forms ethers such as dimethyl croconate where the hydrogen atom of the hydroxyl group is substituted with an alkyl group.
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The term "crown" refers to the resemblance between the structure of a crown ether bound to a cation, and a crown sitting on a person's head. The first number in a crown ether's name refers to the number of atoms in the cycle, and the second number refers to the number of those atoms that are oxygen. Crown ethers are much broader than the oligomers of ethylene oxide; an important group are derived from catechol. Crown ethers strongly bind certain cations, forming complexes.
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The Claisen rearrangement of aryl ethers can also be performed as a photochemical reaction. In addition to the traditional ortho product obtained under thermal conditions (the [3,3] rearrangement product), the photochemical variation also gives the para product ([3,5] product), alternate isomers of the allyl group (for example, [1,3] and [1,5] products), and simple loss of the ether group, and even can rearrange alkyl ethers in addition to allyl ethers. The photochemical reaction occurs via a stepwise process of radical-cleavage followed by bond-formation rather than as a concerted pericyclic reaction, which therefore allows the opportunity for the greater variety of possible substrates and product isomers. The [1,3] and [1,5] results of the photo- Claisen rearrangement are analogous to the photo-Fries rearrangement of aryl esters and related acyl compounds.
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The Zeisel determination or Zeisel test is a chemical test for the presence of esters or ethers in a chemical substance.Prey, V. (1941) Chemische Berichte 74: 350.Lange (1962) J. Org. Chem. 27: 2037.
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Together with enflurane and halothane, it replaced the flammable ethers used in the pioneer days of surgery. Its name comes from being a structural isomer of enflurane, hence they have the same empirical formula.
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Many classes of compounds with C–O–C linkages are not considered ethers: Esters (R–C(=O)–O–R′), hemiacetals (R–CH(–OH)–O–R′), carboxylic acid anhydrides (RC(=O)–O–C(=O)R′).
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Tetraethoxymethane can be used as a solvent and for the alkylation of CH-acidic compounds (e.g. phenols and carboxylic acids). In addition, it reacts with amines, enol ethers and sulfonamides,W. Kantlehner et al.
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Many synthetic ionophores are based on crown ethers, cryptands, and calixarenes. Pyrazole-pyridine and bis-pyrazole derivatives have also been synthesized. These synthetic species are often macrocyclic. Some synthetic agents are not macrocyclic, e.g.
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Dipropyl ether can be synthesized by reacting two molecules of n-propanol in the presence of p-toluenesulfonic acid (a strong acid) and heat, in the same way other symmetrical ethers may be formed.
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Electron-rich arenes are nitrosylated using NOBF4.E. Bosch and J. K. Kochi. "Direct Nitrosation of Aromatic Hydrocarbons and Ethers with the Electrophilic Nitrosonium Cation". Journal of Organic Chemistry, 1994, volume 59, pp. 5573–5586.
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2,3-Dihydrofuran is a heterocyclic compound. It is one of the simplest enol ethers and a position isomer of 2,5-dihydrofuran. It is a colorless volatile liquid. It undergoes lithiation upon treatment with butyl lithium.
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Under dry conditions it has unlimited shelf life. It is soluble in aromatic solvents, whereas LAH is only soluble in ethers. For example, a solution greater than 70 wt.% concentration in toluene is commercially available.
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The toxicity of vinyl ethers has been heavily investigated because they have been used as inhalation anesthetics. The acute LD50 for the closely related methyl vinyl ether is greater than 4 g/kg (rats, oral).
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It was produced industrially from paraformaldehyde and a mixture of chlorosulfonic acid and sulfuric acid.Wilhelm Heitmann, Günther Strehlke, Dieter Mayer “Ethers, Aliphatic” Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. It is also produced as a byproduct in the Blanc chloromethylation reaction, formed when formaldehyde (the monomer, paraformaldehyde or formalin) and concentrated hydrochloric acid are mixed, and is a known impurity in technical grade chloromethyl methyl ether. Because of their carcinogenic potency, the industrial production of chloromethyl ethers ended in most countries in the early 1980s.
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Allyl alcohol is converted mainly to glycidol, which is a chemical intermediate in the synthesis of glycerol, glycidyl ethers, esters, and amines. Also, a variety of polymerizable esters are prepared from allyl alcohol, e.g. diallyl phthalate.
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Quingestrone is a variant of progesterone with improved pharmacokinetics, including higher potency, oral activity, greater lipophilicity, and a longer half-life. Two other progestogens, pentagestrone (never marketed) and pentagestrone acetate (Gestovis, Gestovister), are the 3-cyclopentyl enol ethers of 17α-hydroxyprogesterone and 17α-hydroxyprogesterone acetate, respectively, while progesterone 3-acetyl enol ether (never marketed) is the 3-acetyl enol ether of progesterone. Although it was originally thought that progesterone ethers like quingestrone were prodrugs of progesterone, it was subsequently found that this is not the case and that quingestrone instead seems to be transformed directly into the corresponding alcohols rather than ketones. These alcohols are progesterone metabolites like pregnanolones and pregnanediols, and as some of these metabolites, for instance 3β-dihydroprogesterone, have potent progestogenic activity, this may account for the clinical efficacy of progestogen ethers like quingestrone as progestogens.
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1974, 2397. Ether cleavage is difficult to accomplish with most hydride reagents. However, debenzylation of benzyl aryl ethers may be accomplished with SMEAH.Kametani, T.; Huang, S. P.; Ihara, M.; Fukumoto, K. J. Org. Chem. 1976, 41, 2545.
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Breaking the Ethers is the debut album from collaborative group Tuatara. Released on Epic Records, it was an attempt by members of Luna, the Screaming Trees and R.E.M. to try their hand at experimental, multi-ethnic music.
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Alkali metals also readily form complexes with crown ethers (e.g. 12-crown-4 for Li+, 15-crown-5 for Na+, 18-crown-6 for K+, and 21-crown-7 for Rb+) and cryptands due to electrostatic attraction.
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The grouping of oxygen and sulfur in the periodic table suggests that the chemical properties of ethers and sulfides are somewhat similar, though the extent to which this is true in practice varies depending on the application.
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There have also been significant strides in the synthesis of ethers when using temperatures of 300 °C and up and using weaker alkylating agents to facilitate more efficient synthesis. This methodology helps streamline the synthesis process and makes synthesis on an industrial scale more feasible. The much higher temperature makes the weak alkylating agent more reactive and less likely to produce salts as a byproduct. This method has proved to be highly selective and especially helpful in production of aromatic ethers such as anisole which has increasing industrial applications.
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Trippy Ethers is a series of painting moving away from expressive marks of shapes, and utilizing strokes to create small marks of paint, ranging over the canvas. There is no accumulating image that rises out of the painted surface, but instead the sense of space and dimension is formed in the viewer's mind. Trippy Ethers can be understood as an attempt to reverse the contemporary conditions of information overload. Kelowna Art Gallery describes Phan's series as being "not monotonous...," but as "rich, meditative, contemplative works that invoke a quietude within the viewer".
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Distinguishing between both mechanisms requires consideration of inductive and mesomeric effects that could stabilize or destabilize a potential carbocation in the SN1 pathway. Usage of hydrohalic acids takes advantage of the fact that these agents are able to protonate the ether oxygen atom and also provide a halide anion as a suitable nucleophile. However, as ethers show similar basicity as alcohols (pKa of approximately 16), the equilibrium of protonation lies on the side of the unprotonated ether and cleavage is usually very slow at room temperature. Ethers can be cleaved by strongly basic agents, e.g.
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Both isomers are soluble in simple alcohols, ethers, and chloroform. They are precursors to a variety of useful compounds. Naphthols (both 1 and 2 isomers) are used as biomarkers for livestock and humans exposed to polycyclic aromatic hydrocarbons.
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Phosphonic acid-terminated polyethers are effective superplasticizers. Traditional plasticizers are lignosulphonates as their sodium salt. Superplasticizers are synthetic polymers. Compounds used as superplasticizers include sulfonated naphthalene formaldehyde condensate, sulfonated melamine formaldehyde condensate, acetone formaldehyde condensate and polycarboxylate ethers.
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Polychlorinated biphenyls (PCBs) were once commonly used electrical insulators and heat transfer agents. Their use has generally been phased out due to health concerns. PCBs were replaced by polybrominated diphenyl ethers (PBDEs), which bring similar toxicity and bioaccumulation concerns.
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Prominent components are sabinene, α-pinene, β-pinene and limonene. A major oxygen-containing component is terpinen-4-ol. The oil also contain small amounts of various phenolic compounds and aromatic ethers, e.g. myristicin, elemicin, safrole and methyl eugenol.
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Triethylsilane is the organosilicon compound with the formula (C2H5)3SiH. It is a trialkylsilane. The Si-H bond is reactive. This colorless liquid is used in organic synthesis as a reducing agent and as a precursor to silyl ethers.
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Other fire retardants, such as hexabromocyclododecane and the bromodiphenyl ethers, are additives and are not chemically attached to the material they protect. The use of organobromine fire-retardants is growing but is also controversial because they are persistent pollutants.
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In vinylation reactions, H-X compounds add across the triple bond. Alcohols and phenols add to acetylene to give vinyl ethers. Thiols give vinyl thioethers. Similarly, vinylpyrrolidone and vinylcarbazole are produced industrially by vinylation of 2-pyrrolidone and carbazole.
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Triphenylphosphine dichloride, Ph3PCl2, is a chlorinating agent widely used in organic chemistry. Applications include the conversion of alcohols and ethers to alkyl chlorides, the cleavage of epoxides to vicinal dichlorides and the chlorination of carboxylic acids to acyl chlorides.
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Testosterone, the base androgen of most androgen esters. This is a list of androgen esters, including esters (as well as ethers) of natural androgens like testosterone and dihydrotestosterone (DHT) and synthetic anabolic–androgenic steroids (AAS) like nandrolone (19-nortestosterone).
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Salvia divinorum is a Schedule I controlled substance in the state of Florida making it illegal to buy, sell, or possess in Florida. Its listing in Schedule I reads as follows: This reveals a certain level of incompetence or sloppyness in whomever wrote the statute since Salvia divinorum is a plant, not a chemical, and therefore cannot have isomers, esters, ethers, salts, nor salts of isomers, esters, or ethers. However, this is addressed on the next line of the statute with the listing of salvia A. The Florida statute lists Salvia divnorum and salvia A as separate substances, thusly making possession of the plant illegal as well as the salts of isomers, esters, or ethers derived from the plant. In March 2008 it was reported that Florida state Representative Mary Brandenburg had proposed a bill to make possession of salvia a felony punishable by up to five years in prison.
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Section 1300.01 Definitions relating to controlled substances: > (b) As used in parts 1301 through 1308 and part 1312 of this chapter, the > following terms shall have the meanings specified: > >> (30) The term narcotic drug means any of the following whether produced directly or indirectly by extraction from substances of vegetable origin or independently by means of chemical synthesis or by a combination of extraction and chemical synthesis: >> >>> (i) Opium, opiates, derivatives of opium and opiates, including their isomers, esters, ethers, salts, and salts of isomers, esters, and ethers whenever the existence of such isomers, esters, ethers and salts is possible within the specific chemical designation. Such term does not include the isoquinoline alkaloids of opium. (ii) Poppy straw and concentrate of poppy straw. (iii) Coca leaves, except coca leaves and extracts of coca leaves from which cocaine, ecgonine and derivatives of ecgonine or their salts have been removed.
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The structure of a typical acylsilane. Acylsilanes are a group of chemical compounds sharing a common functional group with the general structure R(CO)-SiR3. Acylsilanes are starting compounds in the Brook rearrangement with vinyl lithium compounds to silyl enol ethers.
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Merck Index, 11th Edition, 7416. p. 1182 It may also contain terpene hydrocarbons, ethers, and esters. The exact composition depends on various factors, such as the variety of pine from which it is produced and the parts of the tree used.
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Appearance of blood red color indicates presence of peroxides. The dangerous properties of ether peroxides are the reason that diethyl ether and other peroxide forming ethers like tetrahydrofuran (THF) or ethylene glycol dimethyl ether (1,2-dimethoxyethane) are avoided in industrial processes.
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Another possible source of phytane and pristane is archaeal ether lipids. Laboratory studies show that thermal maturation of methanogenic archaea generates pristane and phytane from diphytanyl glyceryl ethers (archaeols). In addition, pristane can be derived from tocopherols and methyltrimethyltridecylchromans (MTTCs).
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Selenium dichloride is the inorganic compound with the formula SeCl2. It forms red-brown solutions in ethers. Selenium dichloride has been prepared by treating gray selenium with sulfuryl chloride. Adducts of selenium dichloride with thioethers and thioureas are well characterized.
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The name was originally given to plant products of this nature, in which the other part of the molecule was, in the greater number of cases, an aromatic aldehydic or phenolic compound (exceptions are sinigrin and jalapin or scammonin). It has now been extended to include synthetic ethers, such as those obtained by acting on alcoholic glucose solutions with hydrochloric acid, and also the polysaccharoses, e.g. cane sugar, which appear to be ethers also. Although glucose is the most common sugar present in glucosides, many are known which yield rhamnose or iso- dulcite; these may be termed pentosides.
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In ionic curing processes, an ionic photoinitiator is used to activate the functional group of the oligomers that are going to participate in cross-linking. Typically photopolymerization is a very selective process and it is crucial that the polymerization takes place only where it is desired to do so. In order to satisfy this liquid neat oligomer can be doped with either anionic or cationic photoinitiators that will initiate polymerization only when radiated with light. Monomers, or functional groups, employed in cationic photopolymerization include: styrenic compounds, vinyl ethers, N-vinyl carbazoles, lactones, lactams, cyclic ethers, cyclic acetals, and cyclic siloxanes.
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Trimethylsilyl iodide is used to introduce the trimethylsilyl group onto alcohols (ROH): :R-OH + TMSI → R-OTMS + HI This type of reaction may be useful for gas chromatography analysis; the resultant silyl ether is more volatile than the underivatized original materials. However, for the preparation of bulk trimethylsilylated material, trimethylsilyl chloride may be preferred due to its lower cost. TMSI reacts with alkyl ethers (ROR′), forming silyl ethers (ROSiMe3) and iodoalkanes (RI) that can be hydrolyzed to alcohols (ROH). Trimethylsilyl iodide is also used for the removing of the Boc protecting group, especially where other deprotection methods are too harsh for the substrate.
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Once dissolved, it can be spun into textile fibers (viscose or Lyocell), or chemically reacted to produce derivatized celluloses, such cellulose triacetate, a plastic-like material formed into fibers or films, or cellulose ethers such as methyl cellulose, used as a thickener.
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Erythromycin, a macrolide antibiotic, is one of many naturally occurring macrocycles.Macrocycles are often described as molecules and ions containing twelve or more membered ring. Classical examples include the crown ethers, calixarenes, porphyrins, and cyclodextrins. Macrocycles describe a large, mature area of chemistry.
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NiCl2(dppp) in an effective catalyst for coupling reactions such as the Kumada coupling and Suzuki reactions (example below). It also catalyzes other reactions that convert enol ethers, dithioacetals, and vinyl sulfides to olefins.Tien-Yau Luh; Tien-Min Yuan. "Cross-Coupling Reactions".
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A schematic illustrating the major components of a hydraulic disc brake system. A hydraulic brake is an arrangement of braking mechanism which uses brake fluid, typically containing glycol ethers or diethylene glycol, to transfer pressure from the controlling mechanism to the braking mechanism.
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A generic epoxide. An epoxide is a cyclic ether with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for many applications.
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Dppp can sometimes be used in palladium-catalyzed arylation under Heck reaction conditions to control regioselectivity.Cabri, Walter; Candiani, Ilaria; Bedeschi Angelo; Penco, Sergio"α-Regioselectivity in Palladium-Catalyzed Arylation of Acyclic Enol Ethers" journal= Journal of Organic Chemistry, 1991, volume 57, p. 1481.
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The term cryptand implies that this ligand binds substrates in a crypt, interring the guest as in a burial. These molecules are three-dimensional analogues of crown ethers but are more selective and strong as complexes for the guest ions. The resulting complexes are lipophilic.
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The electride-like salts, described as Ln3+, 2I−, e−, include LaI2, CeI2 and GdI2. Many of the iodides form soluble complexes with ethers, e.g. TmI2(dimethoxyethane)3. Samarium(II) iodide is a useful reducing agent. Ln(II) complexes can be synthesized by transmetalation reactions.
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The products cure from a liquid or gel state to a solid. Curing entails crosslinking by the hydrolysis of silyl ethers: : 2 RSi(OCH3)2R' + H2O → [RSi(OCH3)R']2O + 2 CH3OH This hydrolysis generates siloxane linkages. A catalyst is required for this condensation process.
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Isomers of the repeating unit in polyaspartic acid. Polycarboxylates are used as builders in detergents. Their high chelating power, even at low concentrations, reduces deposits on the laundry and inhibits the crystal growth of calcite. Polycarboxylate ethers (PCE) are used as superplasticizers in concrete production.
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Chemists have demonstrated that many artificial supramolecular systems can be designed that exhibit molecular recognition. One of the earliest examples of such a system are crown ethers which are capable of selectively binding specific cations. However, a number of artificial systems have since been established.
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Fluorination with aminosulfuranes is a chemical reaction that transforms oxidized organic compounds into organofluorine compounds. Aminosulfuranes selectively exchange hydroxyl groups for fluorine, but are also capable of converting carbonyl groups, halides, silyl ethers, and other functionality into organofluorides.Hudlicky, M. Org. React. 1988, 35, 513.
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Carbonyl ylides (RR'C=O+C−RR') can form by ring-opening of epoxides or by reaction of carbonyls with electrophilic carbenes, which are usually prepared from diazo compounds. Oxonium ylides (RR'-O+-C−R'R) are formed by the reaction of ethers with electrophilic carbenes.
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They have one –OH group attached to each carbon. They are further differentiated by the relative orientation (stereochemistry) of these –OH groups. Unlike sugars, which tend to exist as rings, sugar alcohols do not. They can, however, be dehydrated to give cyclic ethers, e.g.
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Hydrobromic acid is mainly used for the production of inorganic bromides, especially the bromides of zinc, calcium, and sodium. It is a useful reagent for generating organobromine compounds. Certain ethers are cleaved with HBr. It also catalyzes alkylation reactions and the extraction of certain ores.
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Silanols condense to give disiloxanes: :2 R3SiOH → R3Si-O-SiR3 \+ H2O The conversions of silyl halides, acetates, and ethers to siloxanes proceed via silanols. The sol-gel process, which entails the conversion of, for example, Si(OEt)4 into hydrated SiO2, proceeds via silanol intermediates.
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New J. Chem. 2014, 38, 845-851. orally as this is easier to pronounce and remember. It is pertinent to mention that Rathore and Kochi Rathore, R.; Kochi, J. K. Radical-Cation Catalysis in the Synthesis of Diphenylmethanes via the Dealkylative Coupling of Benzylic Ethers.
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A major source of man-made VOCs are coatings, especially paints and protective coatings. Solvents are required to spread a protective or decorative film. Approximately 12 billion litres of paints are produced annually. Typical solvents are aliphatic hydrocarbons, ethyl acetate, glycol ethers, and acetone.
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It is probably incompatible with amines, aromatic hydrocarbons, and ethers. Vanadyl nitrate is stable under nitrogen, ozone or oxygen. The liquid is indefinitely stable at room temperature, unlike some other transition metal nitrates that decompose to nitrogen oxides. Over 80 °C it decomposes slowly.
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Pimaric acid is a carboxylic acid from the resin acid group, often found in the oleoresins of pine trees. It can be prepared by dehydration of abietic acid, which it usually accompanies in mixtures like rosin. It is soluble in alcohols, acetone, and ethers.
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Sodium methoxide is a routinely used base in organic chemistry, applicable to the synthesis of numerous compounds ranging from pharmaceuticals to agrichemicals. As a base, it is employed in dehydrohalogenations and various condensations. It is also a nucleophile for the production of methyl ethers.
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Merck Index, 11th edition, 6031. Marketed under the trade names Metopryl and Neothyl, methoxypropane was used as an alternative to diethyl ether because of its greater potency. Its use as an anaesthetic has since been supplanted by modern halogenated ethers which are much less flammable.
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Estradiol, the base estrogen of most estrogen esters. This is a list of estrogen esters, or ester prodrugs of estrogens. It includes esters, as well as ethers, of steroidal estrogens like estradiol, estrone, and estriol and of nonsteroidal estrogens like the stilbestrols diethylstilbestrol and hexestrol.
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MCHM is utilized in about 20 to 25 percent of coal preparation plants in West Virginia. MCHM is not used in the majority of West Virginia's coal preparation plants, because it is only used to produce coal for metallurgical purposes, a type of coal known as "coking coal" and most West Virginia plants process coal that is to be used for the generation of electricity. Diesel fuel was originally used for the froth flotation process, but it was replaced by MCHM because of air emissions regulations. Glycol ethers are a group of solvents based on alkyl ethers of ethylene glycol commonly used in paints.
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When stored in the presence of air or oxygen, ethers tend to form explosive peroxides, such as diethyl ether hydroperoxide. The reaction is accelerated by light, metal catalysts, and aldehydes. In addition to avoiding storage conditions likely to form peroxides, it is recommended, when an ether is used as a solvent, not to distill it to dryness, as any peroxides that may have formed, being less volatile than the original ether, will become concentrated in the last few drops of liquid. The presence of peroxide in old samples of ethers may be detected by shaking them with freshly prepared solution of a ferrous sulfate followed by addition of KSCN.
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Helium at high pressures produces nervous irritation ("anti- anaesthesia"), suggesting that the anaesthetic mechanism(s) may be operated in reverse by this gas (i.e., nerve membrane compression). Also, some halogenated ethers (such as flurothyl) also possess this "anti-anaesthetic" effect, providing further evidence for this theory.
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Akin to the chemistry of alcohols, thiols form sulfides, thioacetals, and thioesters, which are analogous to ethers, acetals, and esters respectively. Thiols and alcohols are also very different in their reactivity, thiols being more easily oxidized than alcohols. Thiolates are more potent nucleophiles than the corresponding alkoxides.
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Nafion, as a superacid, has potential as a catalyst for organic synthesis. Studies have demonstrated catalytic properties in alkylation, isomerization, oligomerization, acylation, ketalization, esterification, hydrolysis of sugars and ethers, and oxidation. New applications are constantly being discovered. These processes, however, have not yet found strong commercial use.
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The general structure of a silyl enol ether Silyl enol ethers in organic chemistry are a class of organic compounds that share a common functional group composed of an enolate bonded through its oxygen end to an organosilicon group. They are important intermediates in organic synthesis.
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HBF4 is used as a catalyst for alkylations and polymerizations. In carbohydrate protection reactions, ethereal fluoroboric acid is an efficient and cost-effective catalyst for transacetalation and isopropylidenation reactions. Acetonitrile solutions cleave acetals and some ethers. Many reactive cations have been obtained using fluoroboric acid, e.g.
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Dichloromethyl methyl ether (HCl2COCH3) is an organic compound that belongs to the class of ethers with a dichloromethyl group and a methyl group. It can be synthesized from methyl formate and a mixture of phosphorus pentachloride and phosphorus oxychlorideOrganic Syntheses, Coll. Vol. 5, p.365 (1973); Vol.
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Sodium phenoxide (sodium phenolate) is an organic compound with the formula NaOC6H5. It is a white crystalline solid. Its anion, phenoxide, also known as phenolate, is the conjugate base of phenol. It is used as a precursor to many other organic compounds, such as aryl ethers.
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Di(propylene glycol) methyl ether is an organic solvent with a variety of industrial and commercial uses.Technical Data Sheet It finds use as a less volatile alternative to propylene glycol methyl ether and other glycol ethers. The commercial product is typically a mixture of four isomers.
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The complex displays a particular affinity for "hard" Lewis bases, such as the oxygen atom in ethers and the nitrogen of amines. It is soluble in nonpolar solvents, even more so than related complexes of acetylacetone and hexafluoroacetylacetone. The fod ligand is a derivative of heptafluorobutyric acid.
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Metal cleaners are used for cleaning stainless steel sinks, faucets, metal trim, silverware, etc. These products contain abrasives (e.g., siliceous chalk, diatomaceous earth, alumina) with a particle size < 20 μm. Fatty alcohol or alkylphenol polyglycol ethers with 7-12 ethylene oxide (EO) units are used as surfactants.
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The International Symposium on Alcohol Fuels (ISAF) is a non-profit international organization which gathers together specialists, technologists, executives and technical experts from alcohol, alcohol fuels, methanol, ethers and bio-fuel industries. ISAF came into being in 1976. The 2011 meeting (ISAF- XIX) will be held in Verona, Italy.
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One of the effects of transannular strain is the difficulty of synthesizing medium-sized rings. Illuminati et al. have studied the kinetics of intramolecular ring closing using the simple nucleophilic substitution reaction of ortho-bromoalkoxyphenoxides. Specifically, they studied the ring closing of 5 to 10 carbon cyclic ethers.
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The aldol reaction may proceed by two fundamentally different mechanisms. Carbonyl compounds, such as aldehydes and ketones, can be converted to enols or enol ethers. These species, being nucleophilic at the α-carbon, can attack especially reactive protonated carbonyls such as protonated aldehydes. This is the 'enol mechanism'.
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For example, the methyl ether in vanillin can be removed by heating near 250 °C with strong base. Stronger nucleophiles such as diorganophosphides (LiPPh2) also cleave aryl ethers under milder conditions. Other strong nucleophiles that have been employed include thiolates salts like EtSNa. Acidic conditions can also be used.
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Butanol, with a four-carbon chain, is moderately soluble. Because of hydrogen bonding, alcohols tend to have higher boiling points than comparable hydrocarbons and ethers. The boiling point of the alcohol ethanol is 78.29 °C, compared to 69 °C for the hydrocarbon hexane, and 34.6 °C for diethyl ether.
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The general structure of an ether. R and R' represent any alkyl or aryl substituent. Not all chemicals with formula R-O-R' are an ether. Ethers are a class of organic compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups.
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Cationic initiators and intermediates characterize cationic ring-opening polymerization (CROP). Examples of cyclic monomers that polymerize through this mechanism include lactones, lactams, amines, and ethers. CROP proceeds through an SN1 or SN2 propagation, chain-growth process. The mechanism is affected by the stability of the resulting cationic species.
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The formation of the ether bond in mammals requires two enzymes, dihydroxyacetonephosphate acyltransferase (DHAPAT) and alkyldihydroxyacetonephosphate synthase (ADAPS), that reside in the peroxisome. Accordingly, peroxisomal defects often lead to impairment of ether-lipid production. Monoalkylglycerol ethers (MAGEs) are also generated from 2-acetyl MAGEs (precursors of PAF) by KIAA1363.
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Abietic acid is considered a "nonhazardous natural substance" in tall oil. In the U.S., it is listed in the Toxic Substances Control Act inventory. Abietic acid is a contact allergen; however, compounds resulting from its oxidation by air elicit stronger responses. It is soluble in alcohols, acetone, and ethers.
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Ethyl vinyl ether is made by reaction of acetylene and ethanol in presence of a base. The alkene portion of the molecule is reactive in many ways. It is prone to polymerization, leading to formation of polyvinyl ethers. Polymerization is typically initiated with Lewis acids such as boron trifluoride.
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Historically, aryl methyl ethers, including natural products such as codeine (O-methylmorphine), have been demethylated by heating the substance in molten pyridine hydrochloride (m.p. 144 °C) at 180 to 220 °C, sometimes with excess hydrogen chloride, in a process known as the Zeisel–Prey ether cleavage. Quantitative analysis for aromatic methyl ethers can be performed by argentometric determination of the N-methylpyridinium chloride formed. The mechanism of this reaction starts with proton transfer from pyridinium ion to the aryl methyl ether, a highly unfavorable step (K < 10–11) that accounts for the harsh conditions required, given the much weaker acidity of pyridinium (pKa = 5.2) compared to the protonated aryl methyl ether (an arylmethyloxonium ion, pKa = –6.7 for aryl = Ph).
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But his original work was mainly in the domain of organic chemistry. Investigation of the cyanic ethers (1848) yielded a class of substances which opened out a new field in organic chemistry, for, by treating those ethers with caustic potash, he obtained methylamine, the simplest organic derivative of ammonia (1849), and later (1851) the compound ureas. In 1855, reviewing the various substances that had been obtained from glycerin, he reached the conclusion that glycerin is a body of alcoholic nature formed on the type of three molecules of water, as common alcohol is on that of one, and was thus led (1856) to the discovery of the glycols or diatomic alcohols, bodies similarly related to the double water type.
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This separation was ended however by the synthesis of urea from inorganic precursors by Friedrich Wöhler in 1828. Other chemists who brought major contributions to organic chemistry include Alexander William Williamson with his synthesis of ethers and Christopher Kelk Ingold, who, among many discoveries, established the mechanisms of substitution reactions.
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Pentabromodiphenyl ether (also known as pentabromodiphenyl oxide) is a brominated flame retardant which belongs to the group of polybrominated diphenyl ethers (PBDEs). Because of their toxicity and persistence, their industrial production is to be eliminated under the Stockholm Convention, a treaty to control and phase out major persistent organic pollutants (POP).
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Tolerated Functional Groups: Ethers R–O–R, R–S–R, Imines RN=CHR. Amides, primary and secondary amines. Carbamates typically do not tolerate the reaction conditions, but tert-butyl carbamates (N-Boc derivatives) survive the transformation. An asymmetric version of this reaction is also known with a TADDOL-based catalyst.
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Starting from a 4,6-disubstituted benzimidazole lead structure, a series of 4,5-biarylimidazoles capable to block both capsaicin and acid-induced calcium influx in TRPV1-expressing Chinese hamster ovary cells. Imidazole (fig. 8a) was identified as a highly potent and orally bioavailable TRPV1. Another class are the diaryl ethers and amines.
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2,3-Sigmatropic rearrangements are a type of sigmatropic rearrangements and can be classified into two types. Rearrangements of allylic sulfoxides, amine oxides, selenoxides are neutral. Rearrangements of carbanions of allyl ethers are anionic. The general scheme for this kind of rearrangement is: center Atom Y may be sulfur, selenium, or nitrogen.
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Solvent- borne, also called oil-based, paints can have various combinations of organic solvents as the diluent, including aliphatics, aromatics, alcohols, ketones and white spirit. Specific examples are organic solvents such as petroleum distillate, esters, glycol ethers, and the like. Sometimes volatile low- molecular weight synthetic resins also serve as diluents.
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Basic ether cleavage is induced by deprotonation in α position.Christoph Elschenbroich: Organometallics, Third, Completely Revised and Extended Edition 2006, Wiley-VCH Weinheim, Germany. . The ether then decomposes into an alkene and an alkoxide. Cyclic ethers allow for an especially quick concerted cleavage, as seen for THF: Image:THF cleavage by RLi.
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500x500px In more specialized applications, diazomethane and homologues are used in Arndt-Eistert synthesis and the Büchner–Curtius–Schlotterbeck reaction for homologation. Büchner-Curtius- Schlotterbeck Reaction. Diazomethane reacts with alcohols or phenols in presence of boron trifluoride (BF3) to give methyl ethers. Diazomethane is also frequently used as a carbene source.
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The solvent composition is typically a mixture of aliphatic hydrocarbons, aromatics, ethers, cellosolves and acetates. This method produces significant VOC (volatile organic compound) and HAP (hazardous air pollutant) emissions. The coatings have good abrasion resistance and high quality, but the high VOC emissions have virtually eliminated their use in can plants.
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It grows in scrubland (batha and phrygana) and rocky areas. Its range is the Mediterranean coast, in Spain, Morocco, Lebanon, Syria, Israel, Cyprus, and Turkey. In the 1980s there was chemical interest in esters and ethers extracted from it. This species has been considered to have abortive and menstruation-inducing properties.
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The dipole moment of 18-crown-6 varies in different solvent and under different temperature. Under 25 °C, the dipole moment of 18-crown-6 is in cyclohexane and in benzene. The synthesis of the crown ethers led to the awarding of the Nobel Prize in Chemistry to Charles J. Pedersen.
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These triflic acid derivative catalysts are very effective in isomerizing straight chain or slightly branched hydrocarbons that can increase the octane rating of a particular petroleum-based fuel. Triflic acid reacts exothermically with alcohols to produce ethers and olefins. triflic acid condensation reaction Dehydration gives the acid anhydride, trifluoromethanesulfonic anhydride, (CF3SO2)2O.
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2]cryptand with two triflate counter ions. The crystal structure of this Ge cryptand[2.2.2] (CF3SO3)2 salt reveals a lack of coordination between the encapsulated Ge(II) cation and the triflate anions. Since these reports, similar cationic Ge(II) complexes have been prepared employing crown ethers, azamacrocycles, and bulky isocyanide ligands.
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Pure Caro's acid is highly explosive. Explosions have been reported at Brown University and Sun Oil. As with all strong oxidizing agents, peroxysulfuric acid should be kept away from organic compounds such as ethers and ketones because of its ability to peroxidize these compounds, creating highly unstable molecules such as acetone peroxide.
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BCl3 hydrolyzes readily to give hydrochloric acid and boric acid: :BCl3 \+ 3 H2O → B(OH)3 \+ 3 HCl Alcohols behave analogously giving the borate esters, e.g. trimethyl borate. Ammonia forms a Lewis adduct with boron trichloride. As a strong Lewis acid, BCl3 forms adducts with tertiary amines, phosphines, ethers, thioethers, and halide ions.
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Oxatriquinane was first described in 2008, and was obtained after a five-step synthesis starting from 1,4,7-cyclononatriene. At the time it had the longest C–O bond lengths (1.54 Å, C–O bonds in ethers are generally ~1.43 Å) and most acute C−O−C angles ever observed in a compound.
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The strong interaction between folic acid and folate receptor was attributed to both hydrogen bonds and hydrophobic interactions. The study of non-covalent interactions is also used to study binding and cooperativity in supramolecular assemblies and macrocyclic compounds such as crown ethers and cryptands, which can act as hosts to guest molecules.
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The crown ethers are often generated in the presence of an alkali metal cation, which organizes the condensing components by complexation. An illustrative macrocyclization is the synthesis of (−)-muscone from (+)-citronellal. The 15-membered ring is generated by ring-closing metathesis. :Synthesis of muscone via RCM Uroporphyrinogen III, biosynthetic precursor to porphyrins.
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Industrially, pine oil is used as a frother in mineral extraction from ores. For example, in copper extraction pine oil is used to condition copper sulfide ores for froth flotation. Therefore, it is important in the industry for the froth flotation process. It has largely been replaced by synthetic alcohols and polyglycol ethers.
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Both M. acetivorans and M. mazei have exceptionally large genomes. As of August 2008, M. acetivorans possessed the largest sequenced archaeal genome with 5,751,492 base pairs. The genome of M. mazei has 4,096,345 base pairs. Methanosarcina cell membranes are made of relatively short lipids, yup primarily of C25 hydrocarbons and C20 ethers.
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Alkynyl ethers and siloxyacetylenes have proven to be the ideal pair for aromatic annulations. The reactions can be run with both activated heterosubstituted alkynes and un-activated acetlyenes. Alkynyl thioethers and ynamines have been used as reactants in the annulation reaction. Conjugated enynes have also been used for benzannulation reactions catalyzed by cobalt.
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3-Dimethylaminoacrolein is obtained by the addition of dimethylamine to the triple bond of propynal (propargyl aldehyde) via a Reppe vinylation. Synthese of Dimethylaminoacrolein from propynal. Propynal is however an inappropriate starting material for industrial synthesis because of its tendency to explode. Vinyl ethers (such as ethyl vinyl ether) are more suited.
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Harrison was educated at Henley Grammar School and the University of Birmingham where he was awarded a Bachelor of Science degree in Chemistry in 1969, followed by a PhD in Organic chemistry in 1972 and a Doctor of Science in Environmental chemistry in 1989. His PhD research investigated sigmatropic reactions of tropolone ethers.
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Azobenzene photoisomerization. The photochromic trans-cis isomerization of azobenzenes has been used extensively in molecular switches, often taking advantage of its shape change upon isomerization to produce a supramolecular result. In particular, azobenzenes incorporated into crown ethers give switchable receptors and azobenzenes in monolayers can provide light-controlled changes in surface properties.
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Acrylic acid (IUPAC: propenoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform.
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For the stoichiometric reactions involving alkali metal or alkaline earth acetylides, work-up for the reaction requires liberation of the alcohol. To achieve this hydrolysis, aqueous acids are often employed. : RR'C(ONa)C≡CR" + CH3COOH → RR'C(OH)C≡CR" + CH3COONa Common solvents for the reaction include ethers, acetals, dimethylformamide, and dimethyl sulfoxide.
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Desoxypipradrol was eventually made a class B drug and placed in Schedule I on 13 June 2012. There were no recorded deaths from the drug between the banning of its import and the banning of its possession. "Esters and ethers of pipradrol" were controlled with the same amendment as class C drugs.
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Purification involves the addition of an aqueous acid such as saturated ammonium chloride solution. This quenches remaining silyl reagent and protonates amine bases, removing them from the reaction mixture. Following extraction, the product can be purified by flash chromatography. Silyl triflate is more reactive and also converts ketones to silyl enol ethers.
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3β-Dihydroprogesterone has been reported to possess about the same progestogenic potency as progesterone in the Clauberg test, whereas 3α-dihydroprogesterone was not assessed. The C3 enol ethers of progesterone are less suited for use via depot injection relative to progestogen esters like hydroxyprogesterone caproate due to their susceptibility to oxidative metabolism.
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PPEs have excellent high temperature properties and good oxidation stability. With respect to volatilities, p-derivatives have the lowest volatilities, and the o-derivatives have the highest volatilities. The opposite is true for flash points and fire points. Spontaneous ignition temperatures of polyphenyl ethers lie between , alkyl substitution reduces this value by ~.
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In 1968 Izatt was on a train ride home when he stopped in Chicago to meet with the physiologist George Eisenman who informed Izatt about Pedersen's paper on crown ethers published only months earlier. Izatt was looking forward to the possibilities of studying these crown ethers with his thermionic titration technique. Izatt called Pedersen and was the first scientist not at DuPont to meet with Pedersen about his discovery and Pedersen supplied him with a sample of his new crown ether compound. Izatt's work on molecular recognition was greatly influenced by his interaction with Pedersen. In Izatt's last visit with Pedersen prior to his death in 1988 he found a personal letter written by Pedersen that stated, “Most men achieve ‘Immortality’ through their progeny.
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Ethyl phenyl ether or phenetole is an organic compound that is an ether. Ethyl phenyl ether has the same properties as some other ethers, such as volatility, explosive vapors, and the ability to form peroxides. It will dissolve in less polar solvents such as ethanol or ether, but not in polar solvents such as water.
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Attempts to find anesthetics with less metabolism led to halogenated ethers such as enflurane and isoflurane. The incidence of hepatic reactions with these agents is lower. The exact degree of hepatotoxic potential of enflurane is debated, although it is minimally metabolized. Isoflurane is essentially not metabolized and reports of associated liver injury are quite rare.
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SN1 mechanisms are operative for compounds that form carbocations easily, while SN2 reactions take place with less ionizable compounds. (3)File:SF4SMech2.png Fluorination of carboxylic acids gives not only the expected trifluoromethyl compounds, but also α-tetrafluorinated ethers. A mechanism to account for both products has been proposed and experimentally supported.Dmowski, W.; Kolinski, A. Pol.
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Milorganite contains metals at levels found safe by EPA when Milorganite is used as directed. The EPA has not regulated levels of environmentally toxic manmade dioxins. Polybrominated diphenyl ethers, a type of "persistent, bioaccumulative and toxic" (PBT) contaminant, were detected in biosolids in 2001. PCBS are occasionally detected despite production being banned since the 1970s.
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Bis(chloromethyl) ether is an organic compound with the chemical formula (CH2Cl)2O. It is a colourless liquid with an unpleasant suffocating odour and it is one of the chloroalkyl ethers. Bis(chloromethyl) ether was once produced on a large scale, but was found to be highly carcinogenic and thus such production has been ceased.
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Solid chloroauric acid is a hydrophilic (ionic) protic solute. It is soluble in water and other oxygen-containing solvents, such as alcohols, esters, ethers, and ketones. For example, in dry dibutyl ether or diethylene glycol, the solubility exceeds 1 mol/L. Saturated solutions in the organic solvents often are the liquid solvates of specific stoichiometry.
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Alcohols add to electrophilically activated alkenes. : R2C=CR2 \+ R–OH → R2CH–C(–O–R)–R2 Acid catalysis is required for this reaction. Often, mercury trifluoroacetate (Hg(OCOCF3)2) is used as a catalyst for the reaction generating an ether with Markovnikov regiochemistry. Using similar reactions, tetrahydropyranyl ethers are used as protective groups for alcohols.
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Reaction with alkoxides or aroxides give ethers in the Williamson ether synthesis; reaction with thiols give thioethers. Alkyl chlorides readily react with amines to give substituted amines. Alkyl chlorides are substituted by softer halides such as the iodide in the Finkelstein reaction. Reaction with other pseudohalides such as azide, cyanide, and thiocyanate are possible as well.
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A minor part is produced from the shortest cotton linters, normally second cut. These are washed mechanically and chemically to remove proteins, waxes, pectins and other polysaccharides. This is bleached to get the required brightness. Dissolving pulp from cellulose linters gives the purest cellulose and is used to manufacture acetate plastics and high-viscosity cellulose ethers.
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Glycidol is prepared by the epoxidation of allyl alcohol.Guenter Sienel, Robert Rieth, Kenneth T. Rowbottom "Epoxides" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. Glycidol is used as a stabilizer for natural oils and vinyl polymers and as a demulsifier. It is used as a chemical intermediate in the synthesis of glycerol, glycidyl ethers, esters and amines.
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The Mukaiyama aldol reaction is the nucleophilic addition of silyl enol ethers to aldehydes catalyzed by a Lewis acid such as boron trifluoride (as boron trifluoride etherate) or titanium tetrachloride.3-Hydroxy-3-Methyl-1-Phenyl-1-Butanone by Crossed Aldol Reaction Teruaki Mukaiyama and Koichi Narasaka Organic Syntheses, Coll. Vol. 8, p.323 (1993); Vol.
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The alkene portion of the molecule is reactive in many ways. It is prone to polymerization, leading to formation of polyvinyl ethers. Polymerization is typically initiated with Lewis acids such as boron trifluoride. This mode of reactivity is analogous to the way vinyl acetate and vinyl chloride can be polymerized to form polyvinyl acetate and polyvinyl chloride, respectively.
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Ge(II) cationic species have been isolated with several crown ether ligands, including [12]crown-4, [15]crown-5, and [18]crown-6. Rupar et al. reported the synthesis of various germanium crown ethers employing GeCl2•dioxane as the source of Ge(II). Trimethylsilyl trifluoromethanesulfonate (Me3SiOTf) was used to displace chloride ligands with a more weakly associating triflate ligand.
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Heterocyclic compounds can be usefully classified based on their electronic structure. The saturated heterocycles behave like the acyclic derivatives. Thus, piperidine and tetrahydrofuran are conventional amines and ethers, with modified steric profiles. Therefore, the study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings.
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The substitution of CO ligands can be induced thermally or photochemically by donor ligands. The range of ligands is large, and includes phosphines, cyanide (CN−), nitrogen donors, and even ethers, especially chelating ones. Alkenes, especially dienes, are effective ligands that afford synthetically useful derivatives. Substitution of 18-electron complexes generally follows a dissociative mechanism, involving 16-electron intermediates.
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An early example is the dialkylation of a nickel dithiolate: :center The corresponding alkylation in the absence of a metal ion would yield polymers. Crown ethers arise from dialkylations that are templated by alkali metals. Other template reactions include the Mannich and Schiff base condensations.Otilia Costisor, W. Linert "Metal mediated template synthesis of ligands" World Scientific Publisher, Singapore, 2004.
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Polyoxymethylene dimethyl ethers (PODE or DMMn) are a class of chemical compounds with the molecular formula H3CO(CH2O)nCH3 where n is typically about 3 to 8. PODE can be produced from methylal and formaldehyde or a formaldehyde equivalent such as paraformaldehyde or trioxane. PODE is used as a diesel fuel additive and as a solvent.
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Beryllium chloride is stable in dry air. Beryllium chloride is a Lewis acid and has been used as a catalyst in some organic reactions. It hydrolyzes, evolving hydrogen chloride: : BeCl2 \+ 2H2O → Be(OH)2 \+ 2 HCl It forms a tetrahydrate, BeCl2•4H2O ([Be(H2O)4]Cl2). BeCl2 is also soluble in oxygenated solvents such as ethers.
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Benzyl potassium is an organopotassium compound with the formula C6H5CH2K that takes the form of an air sensitive orange powder. Like organo-alkali metal reagents in general, benzyl potassium is highly reactive, so much so that its use in coordinating solvents such as ethers and amines is less common than in hydrocarbons, as gradual decomposition occurs.
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PFA tubing is commonly used to handle aggressive chemicals Nafion is a fluoroether with a strongly acidic sulfonic acid substituents Acyclic perfluoroethers are known, e.g. O(C2F5)2, the analogue of diethylether. More interesting and more useful are the cyclic ethers, especially, the epoxides. Thus tetrafluoroethyene oxide and hexafluoropropylene oxide are two of the simplest cyclic perfluoroethers.
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800px left Four years later some unrelated authors cited a skeletal rearrangement accounts for this. Diagram Notice that they are not only interested in ethers, but nitrogen containing Nu's ("TRODAT") The metal is called "Technetium" and is bound by a chelating agent. The authors state that at first the acid is halogenated, the amide is prepared, and reduced.
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Living isobutylene polymerization typically takes place in a mixed solvent system comprising a non-polar solvent, such as hexane, and a polar solvent, such as chloroform or dichloromethane, at temperatures below 0 °C. With more polar solvents polyisobutylene solubility becomes a problem. Initiators can be alcohols, halides and ethers. Co-initiators are boron trichloride, tin tetrachloride and organoaluminum halides.
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Dihydroxymalonic acid can be obtained synthetically by hydrolysis of alloxan with baryta water, by warming caffuric acidThe chemical structure of caffuric acid was given in Allen, W. F. (1932). The preparation and pyrolytic molecular rearrangment [sic] of the 8-ethers of caffeine: And their conversion to 8-methyl and 8-ethylcaffeine. Ann Arbor, Mich.: Edwards Brothers.
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Most carry a UL rating of VTM-0. Polyimide laminates have a flexural strength half life at of 400 hours. Typical polyimide parts are not affected by commonly used solvents and oils – including hydrocarbons, esters, ethers, alcohols and freons. They also resist weak acids but are not recommended for use in environments that contain alkalis or inorganic acids.
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Ester oder sauerstoffsäure Aetherarten. > Ethers du troisième genre. > > Viele mineralische und organische Sauerstoffsäuren treten mit einer Alkohol- > Art unter Ausscheidung von Wasser zu neutralen flüchtigen ätherischen > Verbindungen zusammen, welche man als gepaarte Verbindungen von Alkohol und > Säuren-Wasser oder, nach der Radicaltheorie, als Salze betrachten kann, in > welchen eine Säure mit einem Aether verbunden ist. Translation: > b.
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Esters are more polar than ethers but less polar than alcohols. They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate.
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Ground glass joints are translucent when physically free of debris and clean. Solvents, reaction mixtures, and old grease show up as transparent spots. Grease can be removed by wiping with an appropriate solvent; ethers, methylene chloride, ethyl acetate, or hexanes work well for silicone- and hydrocarbon-based greases. Fluoroether-based greases are quite impervious to organic solvents.
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Cryptands and crown ethers typically do not form inclusion complexes since the guest is bound by forces stronger than van der Waals bonding. If the guest is enclosed on all sides so that it is 'trapped', the compound is known as a clathrate, not an inclusion complex. In molecular encapsulation, a guest molecule is trapped inside another molecule.
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2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple alcohols, ethers, and chloroform.
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Aurolac is an industrial product sold in Romania, designed for use in repairing terracotta stoves, which is commonly abused as an inhalant. The law HG 767/2001 applies restrictions on where and how aurolac, which it uses as a generic term for a variety of substances containing ethers, ketones, acetates, as well as methanol and toluene, can be sold.
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In addition to GTP he developed a living cationic polymerization of vinyl ethers. These two discoveries sparked a burst in university activity on controlled polymerization still going on today. He reintroduced the concept of condensation polymerization of A2B type monomers and named them hyperbranched polymers.[Macromolecules (1992), 25(21), 5561-72 These systems augment the now popular dendritic polymers.
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Hexamethyltungsten is the chemical compound W(CH3)6 also written WMe6. Classified as a transition metal alkyl complex, hexamethyltungsten is an air- sensitive, red, crystalline solid at room temperature; however, it is extremely volatile and sublimes at −30 °C. Owing to its six methyl groups it is extremely soluble in petroleum, aromatic hydrocarbons, ethers, carbon disulfide, and carbon tetrachloride.
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Compared with brandy or whisky the characteristic features of kirsch are (a) that it contains relatively large quantities of higher alcohols and compound ethers, and (b) the presence in this spirit of small quantities of Hydrogen cyanide, partly as such and partly in combination as benzaldehyde-cyanhydrin, to which the distinctive flavour of kirsch is largely due.
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Iain Coldham is an organic chemist and Professor of Organic Chemistry at the University of Sheffield. He obtained his PhD from the University of Cambridge before relocating to Austin, Texas in 1989 for postdoctoral research. His areas of study have included intramolecular trapping of episulfonium ions with amine nucleophiles and the use of triisopropylsilyl enol ethers in organic synthesis.
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The solution may add a solvent like d-limonene, petroleum byproducts, glycol ethers, or butyl agents. The amount of time the pretreatment "dwells" in the carpet should be less than 15 minutes, due to the thorough carpet brushing common to these "very low moisture" systems, which provides added agitation to ensure the pretreatment works fully through the carpet.
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Sebacoyl chloride (or sebacoyl dichloride) is a di-acyl chloride, with formula (CH2)8(COCl)2. A colorless oily liquid with a pungent odor, it is soluble in hydrocarbons and ethers. Sebacoyl chloride is corrosive; like all acyl chlorides, it hydrolyzes, evolving hydrogen chloride. It is less susceptible to hydrolysis though than shorter chain aliphatic acyl chlorides.
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The impact assessment studies reconfirmed that the improper waste and recycling treatment of electronic products with brominated flame retardants can produce dioxins which is not the case with halogen free alternatives. Furthermore, the United States Environmental Protection Agency (US-EPA) has been carrying out a series of projects related to the environmental assessment of alternative flame retardants, the “design for environment” projects on flame retardants for printed wiring boards and alternatives to decabromo diphenylethers and hexabromocyclododecane (HBCD). In 2009, the U.S. National Oceanic and Atmospheric Administration (NOAA) released a report on polybrominated diphenyl ethers (PBDEs) and found that, in contrast to earlier reports, they were found throughout the U.S. coastal zone.NOAA. (2009). An Assessment of Polybrominated Diphenyl Ethers (PBDEs) in Sediments and Bivalves of the U.S. Coastal Zone.
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In accordance, D-ring glucuronides of testosterone and DHT have been found to be cholestatic. Aside from prohormones and testosterone undecanoate, almost all orally active AAS are 17α-alkylated. A few AAS that are not 17α-alkylated are orally active. Some examples include the testosterone 17-ethers cloxotestosterone, quinbolone, and silandrone, which are prodrugs (to testosterone, boldenone (Δ1-testosterone), and testosterone, respectively), the DHT 17-ethers mepitiostane, mesabolone, and prostanozol (which are also prodrugs), the 1-methylated DHT derivatives mesterolone and metenolone (although these are relatively weak AAS), and the 19-nortestosterone derivatives dimethandrolone and 11β-MNT, which have improved resistance to first-pass hepatic metabolism due to their 11β-methyl groups (in contrast to them, the related AAS trestolone (7α-methyl-19-nortestosterone) is not orally active).
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The three-dimensional interior cavity of a cryptand provides a binding site – or host – for "guest" ions. The complex between the cationic guest and the cryptand is called a cryptate. Cryptands form complexes with many "hard cations" including , lanthanoids, alkali metals, and alkaline earth metals. In contrast to crown ethers, cryptands bind the guest ions using both nitrogen and oxygen donors.
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Rhun became King of Gwynedd after Maelgwn. When Vortipor, High King of the Britons, dies, there is a bloody 4-day skirmish over who should succeed him. Sir Bryce is killed in the action and Rhun is forced to abdicate. Noah finds himself on a celestial journey through the ethers, space and time as the missing years in his Chronicle of Ages unfold.
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Larhed, C. Moberg, A. Hallberg: Microwave-accelerated homogeneous catalysis in organic chemistry. Accounts of Chemical Research, 35 (2002) 717-727 and efficient transition metal-catalyzed reactions developed.P. Nilsson, M. Larhed, A. Hallberg: Highly regioselective, sequential, and multiple palladium-catalyzed arylations of vinyl ethers carrying a coordinating auxiliary: An example of a Heck triarylation process. J Am Chem Soc, 123 (2001) 8217-8225P.
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Sigma bond cleavage also occurs on radical cations remote from the site of ionization. This is commonly observed in alcohols, ethers, ketones, esters, amines, alkenes and aromatic compounds with a carbon attached to ring. The cation has a radical on a heteroatom or an unsaturated functional group. The driving force of fragmentation is the strong tendency of the radical ion for electron pairing.
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The leaving site must be a primary carbon, because secondary and tertiary leaving sites generally prefer to proceed as an elimination reaction. Also, this reaction does not favor the formation of bulky ethers like di-tertbutyl ether, due to steric hindrance and predominant formation of alkenes instead.An example for a Williamson ether synthesis to make dipropyl ether. X− product is not shown.
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Finally, hydrofluoric acid is added to give the end product. Because olaflur is produced from a mixture of fatty acids, some molecules have side chains that are longer or shorter than 18 carbon atoms. Other byproducts of the reaction include hydroxyethyl ethers resulting from addition of ethylene oxide to the free hydroxyl groups. The presence of these side products is clinically irrelevant.
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PCTFE is resistant to the attack by most chemicals and oxidizing agents, a property exhibited due to the presence of high fluorine content. However, it swells slightly in halocarbon compounds, ethers, esters and aromatic compounds. PCTFE is resistant to oxidation because it does not have any hydrogen atoms. PCTFE exhibits a permanent dipole moment due to the asymmetry of its repeating unit.
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Fragrances are predominantly monoterpene isoprenoids, with a small amount of benzenoids, although N. jonquilla has both equally represented. Another exception is N. cuatrecasasii which produces mainly fatty acid derivatives. The basic monoterpene precursor is geranyl pyrophosphate, and the commonest monoterpenes are limonene, myrcene, and trans-β-ocimene. Most benzenoids are non- methoxylated, while a few species contain methoxylated forms (ethers), e.g.
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It is characterized by a high boiling point (86 °C) and a low freezing point (−80 °C), allowing a wide range of reaction temperatures. TAME can be used as a safe reaction medium (e.g. condensation reactions, coupling reactions, such as Grignard reactions and Suzuki reactions, as well as metal hydride reductions) and as an extraction solvent to replace dichloromethane, aromatics, and other ethers.
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The health hazards of these chemicals have attracted increasing scrutiny, and they have been shown to reduce fertility in humans at levels found in households. Their chlorine analogs are polychlorinated diphenyl ethers (PCDEs). Because of their toxicity and persistence, the industrial production of some PBDEs is restricted under the Stockholm Convention, a treaty to control and phase out major persistent organic pollutants (POPs).
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Exposure of electronics dismantling workers to polybrominated diphenyl ethers, polychlorinated biphenyls, and organochlorine pesticides in South China. Environ Sci Technol, 41(16), 5647-5653. Young children in the United States tend to carry higher levels of flame retardants per unit body weight than do adults.[59][60] Infants and toddlers are particularly exposed to halogenated flame retardants found in breast milk and dust.
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Benzoin ethers, Acetophenones, Benzoyl Oximes, and Acylphosphines are some examples of cleavage-type photoinitiators. Cleavage readily occurs for the species to give two radicals upon absorption of light, and both radicals generated can typically initiate polymerization. Cleavage type photoinitiators do not require a co-initiator, such as aliphatic amines. This can be beneficial since amines are also effective chain transfer species.
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The two most common problems in this class of reactions are low ortho/para selectivities and dearomatization (the latter is a particularly significant problem for phenols).Zupan, M.; Iskra, J.; Stavber, S. Bull. Chem. Soc. Jpn. 1995, 68, 1655. :File:EFScope5.png Enol ethers and glycals are nucleophilic enough to be fluorinated by Selectfluor.Albert, M.; Dax, K.; Ortner, J. Tetrahedron 1998, 54, 4839.
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Dichlorine monoxide is an effective chlorinating agent. It can be used for either the side-chain or ring chlorination of deactivated aromatic substrates. For activated aromatics such as phenols and aryl-ethers it primarily reacts to give ring halogenated products. It has been suggested that dichlorine monoxide may be the active species in the reactions of HOCl with olefins and aromatic compounds.
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Between 60 and 70% of all propylene oxide is converted to polyether polyols by the process called alkoxylation. These polyols are building blocks in the production of polyurethane plastics. About 20% of propylene oxide is hydrolyzed into propylene glycol, via a process which is accelerated by acid or base catalysis. Other major products are polypropylene glycol, propylene glycol ethers, and propylene carbonate.
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They also found an increase in many other compounds including carbonyl compounds, ethyl esters, Maillard compounds, dioxolanes, and furanic ethers. They carbonyl compounds, as stated previously in the Wietstock experiments, will create Strecker aldehydes, which tend to cause a green apple flavor. Esters are known to cause fruity flavors such as pears, roses, and bananas. Maillard compounds will cause a toasty, malty flavor.
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Many items received in the game are used to heal Pokémon during and outside of battles. A range of items cure various status conditions, such as Antidotes for poisoning and Awakenings for sleep. Revives restore a Pokémon back to health after it has lost all of its HP. Ethers and Elixirs restore the PP of a Pokémon's moves to varying degrees.
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NDIs are also redox-active, forming stable radical anions near -1.10 V vs. Fc/Fc+. Their ability to accept electrons reflects the presence of an extended conjugated ring system and the electron withdrawing groups (carbonyl centers). NDIs are used ins supramolecular chemistry due to their tendency to form charge-transfer complexes with crown ethers, e.g. to give rotaxanes and catenanes.
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Propylene glycol methyl ether (PGME or 1-methoxy-2-propanol) is an organic solvent with a wide variety of industrial and commercial uses. Similar to other glycol ethers, it is used as a carrier/solvent in printing/writing inks and paints/coatings. It also finds use as an industrial and commercial paint stripper. It is used as an antifreeze in diesel engines.
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It is also a component in brake fluid, lubricants, wallpaper strippers, artificial fog and haze solutions, and heating/cooking fuel. In personal care products (e.g. skin cream and lotions, deodorants), DEG is often replaced by selected diethylene glycol ethers. A dilute solution of diethylene glycol can also be used as a cryoprotectant; however, ethylene glycol is much more commonly used.
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Ring-opening polymerization can proceed via radical, anionic, or cationic polymerization as described below. Additionally, radical ROP is useful in producing polymers with functional groups incorporated in the backbone chain that cannot otherwise be synthesized via conventional chain- growth polymerization of vinyl monomers. For instance, radical ROP can produce polymers with ethers, esters, amides, and carbonates as functional groups along the main chain.
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However the Wittig reagent can tolerate many other variants. It may contain alkenes and aromatic rings, and it is compatible with ethers and even ester groups. Even C=O and nitrile groups can be present if conjugated with the ylide- these are the stabilised ylides mentioned above. Bis-ylides (containing two P=C bonds) have also been made and used successfully.
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14(4): p. 1041-1091 : + H2O HO2 \+ OH− Given that the hydroperoxyl radical has a pKa of around 4.8, superoxide predominantly exists in the anionic form at neutral pH. Potassium superoxide is soluble in dimethyl sulfoxide (facilitated by crown ethers) and is stable as long as protons are not available. Superoxide can also be generated in aprotic solvents by cyclic voltammetry.
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In addition, sulfoxides may be carried through multiple synthetic steps before elimination is carried out. (11)File:SelenAlt1.png The combination of silyl enol ethers with palladium(II) acetate (Pd(OAc)2), the Saegusa oxidation, gives enones. However, the reaction requires stoichiometric amounts of Pd(OAc)2 and thus is not amenable to large-scale synthesis. Catalytic variants have been developed. (12)File:SelenAlt2.
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It is a less explosive alternative to diazomethane for the methylation of carboxylic acids. It also reacts with alcohols to give methyl ethers, where diazomethane may not. It has also been employed widely in tandem with GC-MS for the analysis of various carboxylic compounds which are ubiquitous in nature. The fact that the reaction is rapid and occurs readily makes it attractive.
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The reaction is highly suited for substrates with many group functionalities. β-aryl-substituted α,β-unsaturated aldehydes works well with the reaction conditions. Triple bonds directly linked to aldehyde groups or in conjugation with other double bonds can also be subjected to the reaction. Hydroxides, epoxides, benzyl ethers, halides including iodides and even stannanes are quite stable in the reaction.
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Hydrosilylation, also called catalytic hydrosilation, describes the addition of Si-H bonds across unsaturated bonds."Hydrosilylation A Comprehensive Review on Recent Advances" B. Marciniec (ed.), Advances in Silicon Science, Springer Science, 2009. Ordinarily the reaction is conducted catalytically and usually the substrates are unsaturated organic compounds. Alkenes and alkynes give alkyl and vinyl silanes; aldehydes and ketones give silyl ethers.
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The alkene must be electron rich which means that functional groups attached to the alkene must be able to donate electrons. Such alkenes are enol ethers and enamines. The reaction product in the original Povarov reaction is a quinoline. Because the reactions can be carried out with the three components premixed in one reactor it is an example of a multi-component reaction.
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Synthesis of symmetric and unsymmetric NDIs. NTCDI is redox-active, forming stable radical anions near -1.10 V vs. Fc/Fc+. Its ability to accept electrons reflects the presence of an extended conjugated ring system and the electron withdrawing groups (carbonyl centers). NDI is used in supramolecular chemistry owing to its tendency to form charge-transfer complexes with crown ethers, e.g.
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Sulfuryl chloride is used as a source of Cl2. Because it is a pourable liquid, it is considered more convenient than Cl2 to dispense. It is used as a reagent in the conversion of C−H to C−Cl adjacent to activating substituents such as carbonyls and sulfoxides. It also chlorinates alkanes, alkenes, alkynes, aromatics, ethers (such as tetrahydrofuran) and epoxides.
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The Boord olefin synthesis, a reaction he discovered in 1930, is named after him.The synthesis of beta-bromo-alkyl ethers and their use in further synthesis Lloyd C. Swallen and Cecil E. Boord J. Am. Chem. Soc.; 1930; 52(2) pp 651 - 660; It is a classic named reaction with high yields and broad scope.Advanced Organic Chemistry, 4th Edition, Jerry March, 1992.
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Sensitizers are commonly simple ether molecules such as 1,2-bis-(3-methylphenoxy)ethane or 2-benzyloxynapthalene. These two materials melt at approximately 100°C, which is a practical lower limit for thermal coloration. These low-cost ethers are excellent low viscosity solvents for leuco dyes and developers, and this facilitates color formation at a well- defined temperature and with minimum energy input.
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Levan can be in both branched and linear structures of relatively low molecular weight. In the branched version, levan forms a very small, sphere-like structure. This structure has basal chains of 9 units long which contain 2,1 branching, allowing for the methyl ethers to form and create a spherical shape. The ends of levan also tend to contain a glucosyl residue.
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Solvent effects on colors and stability are often attributable to changes in the second coordination sphere. Such effects can be pronounced in complexes where the ligands in the first coordination sphere are strong hydrogen-bond donors and acceptors, e.g. respectively [Co(NH3)6]3+ and [Fe(CN)6]3−. Crown-ethers bind to polyamine complexes through their second coordination sphere.
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Cryptands are more expensive and difficult to prepare, but offer much better selectivity and strength of binding than other complexants for alkali metals, such as crown ethers. They are able to bind otherwise insoluble salts into organic solvents. They can also be used as phase transfer catalysts by transferring ions from one phase to another. Cryptands enabled the synthesis of the alkalides and electrides.
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For over a hundred years the mainstay of inhalational anesthetics remained ether with cyclopropane, which had been introduced in the 1930s. In 1956 halothane was introduced which had the significant advantage of not being flammable. This reduced the risk of operating room fires. In the sixties the halogenated ethers superseded Halothane due to the rare, but significant side effects of cardiac arrhythmias and liver toxicity.
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Only 5–10 mol% of the catalyst in the presence of 3Å molecular sieves (3Å MS) is necessary. The success of the Sharpless epoxidation can be attributed to five major aspects. First, epoxides can be easily converted into diols, aminoalcohols, and ethers, so formation of chiral epoxides is important in the synthesis of natural products. Second, substrate scope is large, including many primary and secondary allylic alcohols.
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Commercial decaBDE is a technical mixture of different PBDE congeners, with PBDE congener number 209 (decabromodiphenyl ether) and nonabromodiphenyl ether being the most common.Joint Research Centre European inventory of Existing Commercial chemical Substances The term decaBDE alone refers to only decabromodiphenyl ether, the single "fully brominated" PBDE.Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polybrominated Biphenyls and Polybrominated Diphenyl Ethers (PBBs and PBDEs).
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In 1904, Fritz Ullmann found out that copper powder could significantly improve the reaction of aryl halides with phenols to give biaryl ethers. This reaction is known as Ullmann condensation. In 1906, I. Goldberg extended this reaction to synthesize an arylamine by reacting aryl halides with an amide in the presence of Potassium Carbonate and CuI. This reaction is known as Goldberg modified Ullmann condensation.
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Methyllithium is the simplest organolithium reagent with the empirical formula CH3Li. This s-block organometallic compound adopts an oligomeric structure both in solution and in the solid state. This highly reactive compound, invariably used as a solution in ethers, is a reagent in organic synthesis as well as organometallic chemistry. Operations involving methyllithium require anhydrous conditions, because the compound is highly reactive toward water.
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To introduce an MTM ether to a hydroxyl group, two methods are mainly used. One is a typical Williamson ether synthesis using an MTM halide as an MTM resource and sodium hydride (NaH) as a base. The other is a special method, in which dimethyl sulfoxide (DMSO) and acetic anhydride (Ac2O) are used. In this case, the reaction proceeds with Pummerer rearrangement: MTM ethers have another advantage.
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Amines may also be prepared from alkyl halides in amine alkylation, the Gabriel synthesis and Delepine reaction, by undergoing nucleophilic substitution with potassium phthalimide or hexamine respectively, followed by hydrolysis. In the presence of a base, haloalkanes alkylate alcohols, amines, and thiols to obtain ethers, N-substituted amines, and thioethers respectively. They are substituted by Grignard reagents to give magnesium salts and an extended alkyl compound.
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Chemical structure of the carbonate ester group A carbonate ester (organic carbonate or organocarbonate) is an ester of carbonic acid. This functional group consists of a carbonyl group flanked by two alkoxy groups. The general structure of these carbonates is R1O(C=O)OR2 and they are related to esters R1O(C=O)R, ethers R1OR2 and also to the inorganic carbonates. Monomers of polycarbonate (e.g.
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Subsequent work demonstrated that many such reactions can be performed rapidly at around room temperature using catalysts such as tetra-n- butylammonium bromide and methyltrioctylammonium chloride in benzene/water systems. An alternative to the use of "quat salts" is to convert alkali metal cations into hydrophobic cations. In the research lab, crown ethers are used for this purpose. Polyethylene glycols are more commonly used in practical applications.
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Elemicin has been synthesized from syringol and allyl bromide using Williamson ether synthesis and Claisen rearrangement. The electrophilic aromatic substitution entering the para- position was made possible by secondary Cope rearrangement. This is due to syringol's allyl aromatic ether being blocked by ethers in both ortho- positions. When blocked the allyl group migrates to the para-position, in this case with yields above 85%.
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In 1995 Rathore and Kochi reported a synthetic procedure to produce various diarylmethanes from their corresponding benzyl methyl ethers. They showed that transformation of bis(methoxymethyl)-p-hydroquinone ether yields corresponding diarylmethane and a polymeric-like material. A reanalysis of this polymeric material showed that it consisted mainly from pillararene. A full characterization of pillararene was first reported in 2008 by Tomoki Ogoshi et al.
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A combination of methyltrichlorosilane and sodium iodide can be used to cleave carbon-oxygen bonds such as methyl ethers. :R'OR + MeSiCl3 \+ NaI + H2O → R'OH + RI + MeSiCl2(OH) + NaCl Esters and lactones can also be cleaved with methyltrichlorosilane and sodium iodide to give the corresponding carboxylic acids. Acetals convert to carbonyl compounds. Thus, methyltrichlorosilane can be used to remove acetal protecting groups from carbonyl compounds under mild conditions.
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Air pollution has been a major issue in Mexico City for decades. Alongside a doubling of the vehicle fleet in Mexico City from 1992 to 2012, and the slow implementation of low-sulphur standards, the use of fuel ethers contributed greatly to an 86% decrease in CO, a 53% decrease in ozone, and a 32% decrease in particulate matter in that 20-year span.
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The reason lies in the higher acidity of the heavier hydrohalic acids as well as the higher nucleophilicity of the respective conjugate base. Fluoride is not nucleophilic enough to allow for usage of hydrofluoric acid to cleave ethers in protic media. Regardless of which hydrohalic acid is used, the rate of reaction is comparably low, so that heating of the reaction mixture is required.
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Ethylene is oxidized to produce ethylene oxide, a key raw material in the production of surfactants and detergents by ethoxylation. Ethylene oxide is also hydrolyzed to produce ethylene glycol, widely used as an automotive antifreeze as well as higher molecular weight glycols, glycol ethers and polyethylene terephthalate. Ethylene undergoes oxidation by palladium to give acetaldehyde. This conversion remains a major industrial process (10M kg/y).
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Chloroauric acid is the precursor used in the purification of gold by electrolysis. Liquid–liquid extraction of chloroauric acid is used for the recovery, concentrating, purification, and analytical determinations of gold. Of great importance is the extraction of HAuCl4 from hydrochloric medium by oxygen-containing extractants, such as alcohols, ketones, ethers and esters. The concentration of gold(III) in the extracts may exceed 1 mol/L.
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There are four main product lines in Park Electrochemical corporation, namely Advanced Composite Materials (for aircraft structures, interiors and radomes. broadgoods, tapes), Nelco Digital Electronic Materials (for multilayer designs), Nelco RF/Microwave Materials, and Advanced Composite Parts (Lightweight assemblies for aerospace applications.). The Company’s products include high-speed, low-loss, engineered formulations, high- temperature modified epoxies, phenolics, polyimides, polyphenylene ethers Signal Integrity (SI) products.
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Peptidic macrocycles Alternating D/L peptide macrocycles are known to self-aggregate into nanotubes, and the resulting nanotubes have been shown to act as ion channels in lipid membranes. center Other architectures use peptide helices as a scaffold to attach other functionalities, such as crown ethers of different sizes. The property of these peptide-crown channels depend strongly on the identity of the capping end-groups.
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In the IUPAC Nomenclature system, ethers are named using the general formula "alkoxyalkane", for example CH3–CH2–O–CH3 is methoxyethane. If the ether is part of a more-complex molecule, it is described as an alkoxy substituent, so –OCH3 would be considered a "methoxy-" group. The simpler alkyl radical is written in front, so CH3–O–CH2CH3 would be given as methoxy(CH3O)ethane(CH2CH3).
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However, the principle of operation might be more precisely described as gas- jet pump, since diffusion plays a role also in other high vacuum pumps. In modern textbooks, the diffusion pump is categorized as a momentum transfer pump. The diffusion pump is widely used in both industrial and research applications. Most modern diffusion pumps use silicone oil or polyphenyl ethers as the working fluid.
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Byproducts can compete with other reagents for benzyne trapping, cause side-reactions, and may require additional purification. Additionally, the HDDA reaction can be useful for substrates with sensitive functionality that might not be tolerated by other benzyne formation conditions (e.g. strong base). The thermally-initiated HDDA reaction has been shown to tolerate esters, ketones, protected amides, ethers, protected amines, aryl halides, alkyl halides, alkenes, and cyclopropanes.
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Kaempferol (3,4′,5,7-tetrahydroxyflavone) is a natural flavonol, a type of flavonoid, found in a variety of plants and plant-derived foods including kale, beans, tea, spinach and broccoli. Kaempferol is a yellow crystalline solid with a melting point of . It is slightly soluble in water and highly soluble in hot ethanol, ethers, and DMSO. Kaempferol is named for 17th-century German naturalist Engelbert Kaempfer.
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Selexol is the trade name for an acid gas removal solvent that can separate acid gases such as hydrogen sulfide and carbon dioxide from feed gas streams such as synthesis gas produced by gasification of coal, coke, or heavy hydrocarbon oils. By doing so, the feed gas is made more suitable for combustion and/or further processing. It is made up of dimethyl ethers of polyethylene glycol.
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In terms of modern finishing products, lac-based finishes are likely to be referred to as shellac, while lacquer refers to synthetic polymers such as nitrocellulose, cellulose acetate butyrate ("CAB"), or acrylic resin dissolved in lacquer thinner, a mixture of solvents such as ketones (acetone, MEK), esters (butyl acetate, methoxypropyl acetate), aromatic hydrocarbons (toluene, xylene), ethers (cellosolve), and alcohols.lacquer thinner Lacquer is more durable than shellac.
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NBS can α-brominate carbonyl derivatives via either a radical pathway (as above) or via acid-catalysis. For example, hexanoyl chloride 1 can be brominated in the alpha-position by NBS using acid catalysis. :α-Bromination of hexanoyl chloride The reaction of enolates, enol ethers, or enol acetates with NBS is the preferred method of α-bromination as it is high-yielding with few side-products.
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This organic compound is a white powdered solid with a slight aromatic, phenolic odor. Categorized as a polychloro phenoxy phenol, triclosan is a chlorinated aromatic compound that has functional groups representative of both ethers and phenols. Phenols often demonstrate antibacterial properties. Triclosan is soluble in ethanol, methanol, diethyl ether, and strongly basic solutions such as a 1M sodium hydroxide solution, but only slightly soluble in water.
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Methoxytoluenes (methylanisoles or cresyl methyl ethers) are a group of three isomeric organic compounds with the formula CH3OC6H4CH3. They consist of a disubstituted benzene ring with methoxy group and one methyl group. All three are colorless flammable liquids which are soluble in organic solvents but poorly soluble in water. They are not of major commercial interest although they are precursors to the corresponding methoxybenzoic acids and methoxybenzaldehydes.
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Catalytic amounts of aqueous CAN allow the efficient synthesis of quinoxaline derivatives. Quinoxalines are known for their applications as dyes, organic semiconductors, and DNA cleaving agents. These derivatives are also components in antibiotics such as echinomycin and actinomycin. The CAN-catalyzed three-component reaction between anilines and alkyl vinyl ethers provides an efficient entry into 2-methyl-1,2,3,4-tetrahydroquinolines and the corresponding quinolines obtained by their aromatization.
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Danheiser was born in New York and received his undergraduate education at Columbia College. While working as an undergraduate under the direction of Gilbert Stork, Danheiser developed a method for the regiospecific alkylation of beta-diketone enol ethers (the "Stork-Danheiser Alkylation"). and employed it in a total synthesis of the spiro sesquiterpene beta-vetivone. Danheiser received his Ph.D. at Harvard University in 1978.
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K3PO4 Tripotassium phosphate has few industrial applications except as a reagent in organic synthesis, where it has been used as a catalyst. Some of the reactions catalysed by K3PO4are listed below: # The hydrate (K3PO4\cdot H2O) has been used to catalyze deprotection of BOC amines. Microwave radiation is used to aid the reaction. # As a catalyst for the synthesis of unsymmetrical diaryl ethers using [Bmim]BF4 as the solvent.
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Grignard reagents are prepared by treating an organic halide (normally organobromine) with magnesium metal. Cyclic or acyclic ethers are required to stabilize the organomagnesium compound. Water and air, which rapidly destroy the reagent by protonolysis or oxidation, are excluded using air-free techniques. Although the reagents still need to be dry, ultrasound can allow Grignard reagents to form in wet solvents by activating the magnesium such that it consumes the water.
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Cram shared the 1987 Nobel Prize in Chemistry with Pedersen but expanding on Pedersen's monumental discovery in macrocyclic chemistry of crown ethers. Pedersen's work was in two-dimensional structures but Cram was able to synthesize similar molecules in three-dimensional space. Cram's synthesis of these three-dimensional molecules provided large gains in the production of enzymes made in labs as these structures have selectivity based on complementary structures.
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They found that as the number of carbons increased, so did the enthalpy of activation for the reaction. This indicates that strain within the cyclic transition states is higher if there are more carbons in the ring. Since transannular strain is the largest source of strain in rings this size, the larger enthalpies of activation result in much slower cyclizations due to transannular interactions in the cyclic ethers.
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Adding an excessive amount of plasticizer will result in excessive segregation of concrete and is not advisable. Depending on the particular chemical used, use of too much plasticizer may result in a retarding effect. Plasticizers are commonly manufactured from lignosulfonates, a by-product from the paper industry. Superplasticizers have generally been manufactured from sulfonated naphthalene condensate or sulfonated melamine formaldehyde, although newer products based on polycarboxylic ethers are now available.
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Saline hydrides are insoluble in conventional solvents, reflecting their non-molecular structures. Ionic hydrides are used as bases and, occasionally, as reducing reagents in organic synthesis. :C6H5C(O)CH3 \+ KH -> C6H5C(O)CH2K + H2 Typical solvents for such reactions are ethers. Water and other protic solvents cannot serve as a medium for ionic hydrides because the hydride ion is a stronger base than hydroxide and most hydroxyl anions.
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Thiols show little association by hydrogen bonding, both with water molecules and among themselves. Hence, they have lower boiling points and are less soluble in water and other polar solvents than alcohols of similar molecular weight. For this reason also, thiols and their corresponding sulfide functional group isomers have similar solubility characteristics and boiling points, whereas the same is not true of alcohols and their corresponding isomeric ethers.
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The Tebbe reagent converts esters and lactones to enol ethers and amides to enamines. In compounds containing both ketone and ester groups, the ketone selectively reacts in the presence of one equivalent of the Tebbe reagent. :500px The Tebbe reagent methylenates carbonyls without racemizing a chiral α carbon. For this reason, the Tebbe reagent has found applications in reactions of sugars where maintenance of stereochemistry can be critical.
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A variety of allylic ethers undergo the Wittig rearrangement—the fundamental requirement is the ability to generate the appropriate carbanion in the substrate. This demands either acidic hydrogens, a reducible functional group, or a carbon-metal bond. Historically, alkenyl, alkynyl, and phenyl groups have been used to acidify the α position. Free terminal alkynes are tolerated, although yields are higher when silyl-protected alkynes are used. (7)File:23Scope3.
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His first original paper (1799) was on the compounds of arsenic and antimony with oxygen and sulphur. In 1807, he began important research into ethers. His researches on sebacic acid (1802) and on bile (1807) deserve mention as well, as does his discovery of hydrogen peroxide (1818).L. J. Thénard (1818) “Observations sur des nouvelles combinaisons entre l’oxigène et divers acides,” Annales de chimie et de physique, 2nd series, vol.
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The PERI studies indicated major pollutants included glycol ethers and 1,2,4-trimethylbenzene. The PERI Toxic 100 Air Polluters list for 2013 ranked the Ball Corporation as 619 in its list of companies producing the most air pollution in the United States. In 2015 Newsweek ranked the Ball Corporation as 70th in their "Green 2015" report, which reviewed the environmental performances of the 500 largest publicly traded companies in the United States.
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FLPs are also reactive toward many unsaturated substrates beyond H2. Some FLPs react with CO2, specifically in the deoxygenative reduction of CO2 to methane. Ethylene also reacts with FLPs: :PCy3 + B(C6F5)3 + C2H4 -> Cy3P+CH2CH2B^{-}(C6F5)3 For acid-base pairs to behave both nucleophilically and electrophilically at the same time offers a method for the ring-opening of cyclic ethers such as THF, 2,5-dihydrofuran, coumaran, and dioxane.
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Atactic polypropylene is an amorphous rubbery material. It can be produced commercially either with a special type of supported Ziegler-Natta catalyst or with some metallocene catalysts. Modern supported Ziegler-Natta catalysts developed for the polymerization of propylene and other 1-alkenes to isotactic polymers usually use as an active ingredient and as a support. The catalysts also contain organic modifiers, either aromatic acid esters and diesters or ethers.
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The high affinity of 18-crown-6 for potassium ions contributes to its toxicity. The smallest crown ether still capable of binding cations is 8-crown-4, with the largest, experimentally confirmed crown ether being 81-crown-27. Crown ethers are not the only macrocyclic ligands that have affinity for the potassium cation. Ionophores such as valinomycin also display a marked preference for the potassium cation over other cations.
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Pentanes are relatively inexpensive and are the most volatile liquid alkanes at room temperature, so they are often used in the laboratory as solvents that can be conveniently and rapidly evaporated. However, because of their nonpolarity and lack of functionality, they dissolve only nonpolar and alkyl-rich compounds. Pentanes are miscible with most common nonpolar solvents such as chlorocarbons, aromatics, and ethers. They are often used in liquid chromatography.
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The Chan–Lam coupling reaction – also known as the Chan–Evans–Lam coupling is a cross-coupling reaction between an aryl boronic acid and an alcohol or an amine to form the corresponding secondary aryl amines or aryl ethers, respectively. The Chan–Lam coupling is catalyzed by copper complexes. It can be conducted in air at room temperature. The more popular Buchwald–Hartwig coupling relies on the use of palladium.
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Hill received his M.Sc. degree in organic chemistry from Cornell University in Ithaca, New York in 1935. His master's thesis was on The action of Grignard reagents on [alpha], [beta]-unsaturated ethers (1935). Denied admission at the University of Virginia, Hill applied successfully for a Rosenwald Fellowship to complete his doctorate at Cornell. He received $1,500 and was awarded his Ph.D. in organic chemistry by Cornell in 1941.
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Uranyl chloride, UO2Cl2 is an unstable, bright yellow coloured chemical compound of uranium. It forms large sand-like crystals which are highly soluble in water, alcohols, and ethers. Uranyl chloride and its two hydrates, UO2Cl2·H2O and UO2Cl2·3H2O, decompose in the presence of light, a fact discovered by Adolph Gehlen in 1804. This photosensitivity periodically attracted scientific curiosity and various unsuccessful attempts to develop photographic applications using the salts.
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18-Crown-6 is an organic compound with the formula [C2H4O]6 and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. It is a white, hygroscopic crystalline solid with a low melting point. Like other crown ethers, 18-crown-6 functions as a ligand for some metal cations with a particular affinity for potassium cations (binding constant in methanol: 106 M−1). The point group of 18-crown-6 is S6.
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138.3 (2009): 616-32. Implicated in the decline of Orca populations in the Pacific Northwest, these widespread contaminants pose a large problem for conservation efforts. While many chemicals can be found in the tissues of Orca, the most common are DDT, an insecticide, polybrominated diphenyl ethers, or PBDEs and polychlorinated biphenyls, or PCBs. Each of these have detrimental physiological effects on orca,Ross, P.S, G.M Ellis, et al.
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In organic synthesis, CAN is useful as an oxidant for many functional groups (alcohols, phenols, and ethers) as well as C–H bonds, especially those that are benzylic. Alkenes undergo dinitroxylation, although the outcome is solvent-dependent. Quinones are produced from catechols and hydroquinones and even nitroalkanes are oxidized. CAN provides an alternative to the Nef reaction; for example, for ketomacrolide synthesis where complicating side reactions usually encountered using other reagents.
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Anslyn and Dougherty, Modern Physical Organic Chemistry, University Science Books, 2006, Transannular strain can also be demonstrated in other cyclo-organic molecules, such as lactones, lactams, ethers, cycloalkenes, and cycloalkynes. These compounds are not without significance, since they are particularly useful in the study of transannular strain. Furthermore, transannular interactions are not relegated to only conflicts between hydrogen atoms, but can also arise from larger, more complicated substituents interacting across a ring.
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The sugars, chelating agents in lignosulfonates such as aldonic acids and extractive compounds are mainly responsible for set retardation. These low range water reducing dispersants are commonly manufactured from lignosulfonates, a by-product from the paper industry. High range superplasticizers (dispersants) have generally been manufactured from sulfonated naphthalene condensate, although polycarboxylic ethers represent more modern alternatives. Both of these high range water reducers are used at 1/2 to 1/3 of the lignosulfonate types.
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Because both enantiomers are found in nature, and because ethyl lactate is easily biodegradable, it is considered to be a "green solvent." Due to its relatively low toxicity, ethyl lactate is used commonly in pharmaceutical preparations, food additives, U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition and fragrances. Ethyl lactate is also used as solvent for nitrocellulose, cellulose acetate, and cellulose ethers."Industrial Solvents Handbook" by Ernest W. Flick.
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Nriagu JO Moore PB eds Springer Verlag Berlin NY. The primitive Amitermitinae species are most numerous in those regions at present. The development of at least 25 fundamentally different sesquiterpenes and several unique cyclic ethers for termite defense in the Amitermitinae Prestwick GD (1983) The chemical defenses of termites. Sci. American 249; pp. 78-87. hint at considerable success and large numbers in the early years for such systems must be elaborate to evolve.
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The first two halogenated ethers were methoxyflurane and enflurane. These in turn were replaced by the current standards of isoflurane, sevoflurane, and desflurane in the eighties and nineties although methoxyflurane remains in use for prehospital anesthesia in Australia as Penthrox. Halothane remains in common place throughout much of the developing world. Many new intravenous and inhalational anesthetics were developed and brought into clinical use during the second half of the 20th century.
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Various methods exist to introduce this functionality. Carboxylic acids can be converted to trifluoromethyl groups by treatment with sulfur tetrafluoride and trihalomethyl compounds, particularly trifluoromethyl ethers and trifluoromethyl aromatics, are converted into trifluoromethyl compounds by treatment with antimony trifluoride/antimony pentachloride (the Swarts reaction). Another route to trifluoromethyl aromatics is the reaction of aryl iodides with trifluoromethyl copper. Finally, trifluoromethyl carbonyls can be prepared by reaction of aldehydes and esters with Ruppert's reagent.
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Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula NaBH4. This white solid, usually encountered as a powder, is a reducing agent that finds application in chemistry, both in the laboratory and on an industrial scale. It has been tested as pretreatment for pulping of wood, but is too costly to be commercialized. The compound is soluble in alcohols, certain ethers, and water, although it slowly hydrolyzes.
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Because many halogenated flame retardants are fat- soluble, they accumulate in fatty areas such as breast tissue and are mobilized into breast milk, delivering high levels of flame retardants to breast-feeding infants.[51] PBDEs also cross the placenta, meaning infants are exposed in utero.Zhao, Y., Ruan, X., Li, Y., Yan, M., & Qin, Z. (2013). Polybrominated diphenyl ethers (PBDEs) in aborted human fetuses and placental transfer during the first trimester of pregnancy.
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Kolliphor EL, formerly known as Cremophor EL, is the registered trademark of BASF Corp. for its version of polyethoxylated castor oil. It is prepared by reacting 35 moles of ethylene oxide with each mole of castor oil. The resulting product is a mixture (CAS number 61791-12-6): the major component is the material in which the hydroxyl groups of the castor oil triglyceride have ethoxylated with ethylene oxide to form polyethylene glycol ethers.
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Minor components are the polyethyelene glycol esters of ricinoleic acid, polyethyelene glycols and polyethyelene glycol ethers of glycerol. Kolliphor EL is a synthetic, nonionic surfactant used to stabilize emulsions of nonpolar materials in water. Kolliphor EL is an excipient or additive in drugs. Therapeutically, modern drugs are rarely given in a pure chemical state, so most active ingredients are combined with excipients or additives such as Kolliphor EL. See page 1/49, Methods and Materials.
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BINAP is used in organic synthesis for enantioselective transformations catalyzed by its complexes of ruthenium, rhodium, and palladium. As pioneered by Ryōji Noyori and his co-workers, rhodium complexes of BINAP are useful for the synthesis of (–)-menthol. Silver complexes are also important; BINAP-AgF can be used to enantioselectively protonate silyl enol ethers. Subsequent studies revealed that related diphosphines with a narrower dihedral angle between the aromatic faces give catalysts that are more enantioselective.
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Etheroleic acid has systematic name 12-[1′E-hexenyloxy]-9Z,11Z-dodecadienoic acid. Etherolenic acid has systematic name (9Z,11E,1'E,3'Z)-12-(1',3'-Hexadienyloxy)-9,11-dodecadienoic acid. The physiological significance of divinyl ethers is still not fully studied. As infection of potato leaves leads to increased levels of divinyl ether synthase, it was suggested that this pathway could be of importance in the defense of plants against attacking pathogens.
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The selectivity in the reaction is due to the stronger electron withdrawing power of the esters compared to the ethers. A stronger electron withdrawing substituent leads to a greater destabilization of the oxocarbenium ion. This slows this reaction pathway, and allows for disaccharide formation to occur with the benzylated sugar. Other effective electron withdrawing groups that have shown selectivity are halogens and azido groups, while deoxygenation has been proven an effective tool in “arming” sugars.
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Lithium borohydride (LiBH4) is a tetrahydroborate and known in organic synthesis as a reducing agent for esters. Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.Luca Banfi, Enrica Narisano, Renata Riva, Ellen W. Baxter "Lithium Borohydride" e-EROS Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons. .
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Such groups deactivate (slow) the reaction and directs the electrophilic nitronium ion to attack the aromatic meta position. Deactivating meta-directing substituents include sulfonyl, cyano groups, keto, esters, and carboxylates. Nitration can be accelerated by activating groups such as amino, hydroxy and methyl groups also amides and ethers resulting in para and ortho isomers. The direct nitration of aniline with nitric acid and sulfuric acid, according to one source,Web resource: warren-wilson.
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Sodium phenoxide is a moderately strong base. Acidification gives phenol: :PhOH ⇌ PhO− \+ H+ (K = 10−10) Alkylation affords phenyl ethers: :NaOC6H5 \+ RBr → ROC6H5 \+ NaBr The conversion is an extension of the Williamson ether synthesis. With acylating agents, one obtains esters: :NaOC6H5 \+ RC(O)Cl → RCO2C6H5 \+ NaCl Sodium phenoxide is susceptible to certain types of electrophilic aromatic substitutions. For example, it reacts with carbon dioxide to form 2-hydroxybenzoate, the conjugate base of salicylic acid.
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Organobromine compounds, also called organobromides, are organic compounds that contain carbon bonded to bromine. The most pervasive is the naturally produced bromomethane. One prominent application of synthetic organobromine compounds is the use of polybrominated diphenyl ethers as fire-retardants, and in fact fire-retardant manufacture is currently the major industrial use of the element bromine. A variety of minor organobromine compounds are found in nature, but none are biosynthesized or required by mammals.
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Benzyl alcohol is used as a general solvent for inks, waxes, shellacs, paints, lacquers, and epoxy resin coatings. Thus it can be used in paint strippers, especially when combined with compatible viscosity enhancers to encourage the mixture to cling to painted surfaces. It is a precursor to a variety of esters and ethers, used in the soap, perfume, and flavor industries. E.g. benzyl benzoate, benzyl salicylate, benzyl cinnamate, dibenzyl ether, benzyl butyl phthalate.
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2-Ethoxyethanol, also known by the trademark Cellosolve or ethyl cellosolve, is a solvent used widely in commercial and industrial applications. It is a clear, colorless, nearly odorless liquid that is miscible with water, ethanol, diethyl ether, acetone, and ethyl acetate. 2-Ethoxyethanol is manufactured by the reaction of ethylene oxide with ethanol. As with other glycol ethers, 2-ethoxyethanol has the useful property of being able to dissolve chemically diverse compounds.
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Mesoxalic acid can be obtained synthetically by hydrolysis of alloxan with baryta water, by warming caffuric acidThe chemical structure of caffuric acid was given in Allen, W. F. (1932). The preparation and pyrolytic molecular rearrangment [sic] of the 8-ethers of caffeine: And their conversion to 8-methyl and 8-ethylcaffeine. Ann Arbor, Mich.: Edwards Brothers. with lead acetate solution, Henry Enfield Roscoe (1888), A Treatise on Chemistry, volume 3, part2 Organic Chemistry, p. 161.
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The convulsant properties of flurothyl pose a challenge to unifying theories of general anesthetics such as the Meyer- Overton hypothesis (see Theories of general anaesthetic action). A variety of halogenated ethers (e.g., isoflurane, sevoflurane) and diethyl ether itself are general anesthetics, and flurothyl is a substituted diethyl ether. Even more strikingly, a structural isomer of flurothyl known as ‘iso-flurothyl’ (1,1,1,3,3,3-hexafluoro-2-methoxypropane) induces general anesthesia and not convulsions in mice and dogs.
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A 2,4-dichloro-substituted phenyl ring at the pyrazole 1-position is preferred for affinity as well as for the activity. It has been shown that additional halogens on this phenyl ring decrease affinity. It is also favorable to have a ring substitution at the 3-carboxamide group, such as the 1-piperidinyl group in rimonabant. Replacement of the amino piperidinyl substituent by alkyl amides, ethers, ketones, alcohols or alkanes resulted mostly in decreased affinity.
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Significantly, the aza-Cope/Mannich reaction occurs in a single step with excellent yield. This procedure is easily applied to condensation of amino ethers (shown below), where the alcohol has been methylated first. After the aza-Cope/Mannich reaction is carried out, the ketone is formed by addition of NaOH. The amine, in this simple case, cannot form the iminium ion from basic ketones; subsequent methods found ways of incorporating ketones into the reaction.
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Yoichiro Nambu, the 2008 Nobel Laureate in Physics Many Japanese Americans have also gained prominence in science and technology. In 1979, biochemist Harvey Itano became the first Japanese American elected to the United States National Academy of Sciences. Charles J. Pedersen won the 1987 Nobel Prize in Chemistry for his methods of synthesizing crown ethers. Yoichiro Nambu won the 2008 Nobel Prize in Physics for his work on quantum chromodynamics and spontaneous symmetry breaking.
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Since all cellulose ethers are hygroscopic, they will absorb moisture from surroundings if left exposed from original packaging. Thus, moisture must be tested and weight corrected to ensure adequate amount of dry active material are apportioned for usage. Moisture is tested by weighing a sample of X grams on an analytic scale, and drying the sample in an oven at 105 °C for 2 hours, then weighing the sample again on the same scale.
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In the Ullmann condensation or Ullmann-type reaction is the copper-promoted conversion of aryl halides to aryl ethers, aryl thioethers, aryl nitriles, and aryl amines. These reactions are examples of cross-coupling reactions. Ullmann-type reactions are comparable to Buchwald–Hartwig reactions but usually require higher temperatures. Traditionally these reaction requires high-boiling polar solvents such as N-methylpyrrolidone, nitrobenzene, or dimethylformamide and high temperatures (often in excess of 210 °C) with stoichiometric amounts of copper.
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The synthesis by De Clermont and Moschnin was based on the earlier work by Alexander Williamson (who is well known for the Williamson-synthesis of ethers). Their synthesis made use of ethyl iodide and silver salts to form esters in combination with pyrophosphate. :Ag4P2O7 \+ 4 EtI → [(EtO)2P(O)]2O + 4 AgI Commercial routes to TEPP often use methods developed by Schrader, Woodstock, and Toy. Triethyl phosphate reacts with phosphorus oxychloride (Schrader-method) or phosphorus pentoxide (Woodstock-method).
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The Bellus–Claisen rearrangement is the reaction of allylic ethers, amines, and thioethers with ketenes to give γ,δ-unsaturated esters, amides, and thioesters. This transformation was serendipitously observed by Bellus in 1979 through their synthesis of a key intermediate of an insecticide, pyrethroid. Halogen substituted ketenes (R1, R2) are often used in this reaction for their high electrophilicity. Numerous reductive methods for the removal of the resulting α-haloesters, amides and thioesters have been developed.
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Much attention has been given to the non-sugar parts (aglyca) of the molecules; the constitutions of many have been determined, and the compounds synthesized; and in some cases the preparation of the synthetic glucoside effected. The simplest glucosides are the alkyl ethers which have been obtained by reacting hydrochloric acid on alcoholic glucose solutions. A better method of preparation is to dissolve solid anhydrous glucose in methanol containing hydrochloric acid. A mixture of alpha- and beta-methylglucoside results.
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The methyl groups come from methyl ethers present in the lignin. Oxidation of dimethyl sulfide with nitrogen dioxide produces dimethyl sulfoxide (DMSO). Also one of the very wide uses of lignosulfonates is deflocculation of clays used in drilling fluids in the oil and gas industry. Furthermore, Lignosulphates are being researched for use in Enhanced oil recovery (EOR) due to their ability to reduce IFT in foams, allowing for improved sweep efficiency, and hence increased recovery factor.
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To modulate the reactivity between monomer and growing polymeric chain is another approach to enhance sequence control. The rationale for this method is that monomer has to be activated with first catalyst at beginning as a dormant species, which could then participate into polymerization as the second catalyst is introduced. A real example is utilization of HI as first catalyst and ZnI2 as second catalyst to achieve sequence-controlled polymerization of vinyl ethers and styrene derivatives.
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Low molecular weight poly(ethylene glycol) (PEG) or other ethers or aprotic organic solvents with high dielectric constant like dimethylsulfoxide (DMSO) can also be mixed the SPE matrix. UV and thermal crosslinking are useful ways to polymerize in-situ the GPE directly in contact with the electrodes for a perfectly adherent interface. Values of ionic conductivity of few mS cm−1 can be easily achieved with GPEs, as demonstrate the numerous research articles published on the argument.
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Ether synthesis by reaction of salicylaldehyde with chloroacetic acid and sodium hydroxideThe Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol (alkoxide). This reaction was developed by Alexander Williamson in 1850. (Link to excerpt.) Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an SN2 reaction. This reaction is important in the history of organic chemistry because it helped prove the structure of ethers.
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Biodiesel from vegetable oil sources have been recorded as having a cetane number range of 46 to 52, and animal-fat based biodiesels cetane numbers range from 56 to 60. Dimethyl ether is a potential diesel fuel as it has a high cetane rating (55-60) and can be produced as a biofuel. Most simple ethers, including liquid ones, such as diethyl ether can be used as diesel fuels, although the lubricity can be of concern.
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"Dinitrochlorohydrin" and "tetranitrodiglycerin" are also likely candidates, though no current use is known. The polynitrates of long chain and aromatic hydrocarbons are invariably room temperature solids, but many are soluble in simple alcohols or ethers in high proportion, and may be useful in this state. Hydrazine, ethylene oxide, hydrogen peroxide (especially in its German World War II form as T-Stoff), and nitromethane are common rocket monopropellants. As noted the specific impulse of monopropellants is lower, p.
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Polybrominated diphenyl ethers or PBDEs, are a class of organobromine compounds that are used as flame retardants. Like other brominated flame retardants, PBDEs have been used in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics, polyurethane foams, and textiles. They are structurally akin to the polychlorinated biphenyls (PCBs) and other polyhalogenated compounds, consisting of two halogenated aromatic rings. PBDEs are classified according to the average number of bromine atoms in the molecule.
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Narrow-range ethoxylates (NREs) are fatty alcohol polyglycol ethers with a narrow homolog distribution and are known nonionic surfactants. They can be produced industrially, for example, by the addition of ethylene oxide onto fatty alcohols in the presence of suitable catalysts (layer compounds which have been calcined or hydrophobized with fatty acids).Reviews on this subject are presented, for example, by M. Cox in J. Am. Oil Chem. Soc. 67, 599 (1990) and by H. Hensen et al.
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Using the standard Dess–Martin periodinane conditions, alcohols can be oxidized to aldehydes/ketones without affecting furan rings, sulfides, vinyl ethers, and secondary amides. Allylic alcohols are easily oxidized using DMP, which are typically difficult to convert to their respective carbonyls using the typical oxidants. Myers and coworkers determined that DMP could oxidize N-protected- amino alcohols, without epimerization (unlike most other oxidants, including Swern oxidation). These protected amino alcohols can be very important in the pharmaceutical industry.
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The Mitsunobu reaction has been applied in the synthesis of aryl ethers: Mitsunobu reaction application With these particular reactants the conversion with DEAD fails because the hydroxyl group is only weakly acidic. Instead the related 1,1'-(azodicarbonyl)dipiperidine (ADDP) is used of which the betaine intermediate is a stronger base. The phosphine is a polymer-supported triphenylphosphine (PS-PPh3). The reaction has been used to synthesize quinine, colchicine, sarain, morphine, stigmatellin, eudistomin, oseltamivir, strychnine, and nupharamine.
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The reaction can begin with either an ortho- isocyanostyrene or a 2-alkenylthioanilide derivative, both forming the indole through Radical cyclization via an α-stannoimidoyl radical. The R group can be a range of both basic and acidic sensitive functional groups such as esters, THP ethers, and β-lactams. In addition the reaction is not stereospecific, in that both the cis and trans isoform can be used to obtain the desired product. Fukuyama Indole Synthesis with either starting material.
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Lithium cyclopentadienide is commercially available as a solution in THF. It is prepared by treating cyclopentadiene with butyllithium: :C5H6 \+ LiC4H9 -> LiC5H5 \+ C4H10 Crystalline solvent-free LiCp, which is rarely encountered, is a "polydecker" sandwich complex, consisting of an infinite chain of alternating Li+ centers sandwiched between μ-η5:η5-C5H5 ligands. In the presence of amines or ethers, LiCp gives adducts, e.g. (η5-Cp)Li(TMEDA). LiCp is a common reagent for the preparation of cyclopentadienyl complexes.
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Like other butanols, 2-butanol has low acute toxicity. The is 4400 mg/kg (rat, oral). Several explosions have been reported during the conventional distillation of 2-butanol, apparently due to the buildup of peroxides with the boiling point higher than that of pure alcohol (and therefore concentrating in the still pot during distillation). As alcohols, unlike ethers, are not widely known to be capable of forming peroxide impurities, the danger is likely to be overlooked.
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It is through the replay of such memories that so-called hauntings are often created. But the ethers may be reserved for a later lecture: in the mean time let us refer to the matter at hand. As previously mentioned, the Light Ether brings virtues from higher spheres down into this one, and this requires elaboration. There is a chain of descent from the First Cause, which some call God, all the way to our physical world.
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From p. 928: "Ils sont constitués par une principe oxygéné, la safrol C10H10O2 … " (They [i.e., the fractions of essential oil that are safrole] are composed of an oxygenated substance, safrole C10H10O2 … ) They observed its reaction with bromine, suggesting the presence of an allyl group.(Grimaux & Ruotte, 1869), p. 929. By 1884, the German chemist Theodor Poleck (1821–1906) suggested that safrole was a derivative of benzene, to which two oxygen atoms were joined as epoxides (cyclic ethers).
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Quingestrone (Enol-Luteovis), a progesterone ether marketed in Italy. Progesterone 3-acetyl enol ether (progesterone acetate), a progest-erone ether that was never marketed. Although it cannot be esterified, progesterone possesses ketone groups at the C3 and C20 positions, and for this reason, it is possible to etherify it; that is, progesterone ethers are possible. Quingestrone (Enol-Luteovis) is a progesterone ether (specifically, the 3-cyclopentyl ether of progesterone) that has been marketed in Italy as an oral contraceptive.
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It can be used to synthesise (diphenyl)methyl esters and ethers with carboxylic acids and alcohols respectively. It can also generate the (diphenyl)methyl carbene and nitrogen gas upon illumination by ultraviolet light or heating. It can also be electrolysed to form the Ph2CN anion, which can decompose to form the Ph2C− anion radical. If carried out in dimethylformamide and tetrabutylammonium perchlorate, these can react to form benzophenone azine, which has the formula Ph2C=N-N=CPh2.
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The reaction can be conducted in gas phase and in solution. center The molecule has a symmetric tetrahedral cage- like structure, similar to adamantane, whose four "corners" are nitrogen atoms and "edges" are methylene bridges. Although the molecular shape defines a cage, no void space is available at the interior for binding other atoms or molecules, unlike crown ethers or larger cryptand structures. The molecule behaves like an amine base, undergoing protonation and N-alkylation (e.g. Quaternium-15).
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Norbadione A has seven acid-base functional groups, among which are two enolic and two carboxylic acid moieties. These functional groups confer water-solubility to the molecule. It selectively complexes cesium cations (Cs+), with an efficiency comparable to that of some calixarenes or crown ethers. It has been investigated for its ability to provide a protective effect against the damaging effects of ionizing radiation, an effect attributed to its ability to protect DNA-related targets from irradiation.
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In organic chemistry the Brook rearrangement refers to any [1,n] carbon to oxygen silyl migration. The rearrangement was first observed in the late 1950s by Canadian chemist Adrian Gibbs Brook (1924–2013), after which the reaction is named. These migrations can be promoted in a number of different ways, including thermally, photolytically or under basic/acidic conditions. In the forward direction, these silyl migrations produce silyl ethers as products which is driven by the stability of the oxygen-silicon bond.
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Another strategy that has been explored is the stabilization of reactions that develop partial negative charges in the transition state. Examples of successful applications are most commonly reactions that are approximated concerted and pericyclic in nature. During the course of the reaction, one fragment develops partial negative character and the transition state can be stabilized by accepting hydrogen bond(s). A demonstrative example is the catalysis of Claisen rearrangements of ester-substituted allyl vinyl ethers reported by the Jacobsen research group.
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Structural formula of 3,4-Epoxycyclohexylmethyl-3’,4’-epoxycyclohexane carboxylate There are two common types of aliphatic epoxy resins: those obtained by epoxidation of double bonds (cycloaliphatic epoxides and epoxidized vegetable oils) and those formed by reaction with epichlorohydrin (glycidyl ethers and esters). Cycloaliphatic epoxides contain one or more aliphatic rings in the molecule on which the oxirane ring is contained (e.g. 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate). They are produced by the reaction of a cyclic alkene with a peracid (see above).
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368x368px As suggested previously, the high Lewis acidity of boroles allows the ready formation of Lewis acid–base adducts with a variety of different donor molecules. This simplest case of reactivity has already been realised in the early days and has frequently been used to highlight the antiaromatic nature of boroles. Pyridines, ethers, phosphines, and different carbene species have been successfully attached to the unsaturated boron center. In general, such reactions are facile and proceed quantitatively, facilitating their isolation in high yield.
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The Hofmann–Martius rearrangement in organic chemistry is a rearrangement reaction converting an N-alkylated aniline to the corresponding ortho and / or para aryl-alkylated aniline. The reaction requires heat, and the catalyst is an acid like hydrochloric acid. :The Hofmann–Martius rearrangement When the catalyst is a metal halide the reaction is also called the Reilly–Hickinbottom rearrangement. The reaction is also known to work for aryl ethers and two conceptually related reactions are the Fries rearrangement and the Fischer–Hepp rearrangement.
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The materials are used in elastomer, sealant, and adhesive applications that require superior weatherability, and resistance to chemical and environmental attack. Natural oil polyols derived from castor oil and other vegetable oils are used to make elastomers, flexible bunstock, and flexible molded foam. Co-polymerizing chlorotrifluoroethylene or tetrafluoroethylene with vinyl ethers containing hydroxyalkyl vinyl ether produces fluorinated (FEVE) polyols. Two-component fluorinated polyurethanes prepared by reacting FEVE fluorinated polyols with polyisocyanate have been used to make ambient cure paints and coatings.
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Polybrominated diphenyl ethers (PBDEs) are a class of compounds found in flame retardants used in plastic cases of televisions and computers, electronics, carpets, lighting, bedding, clothing, car components, foam cushions and other textiles. Potential health concern: PBDE's are structurally very similar to Polychlorinated biphenyls (PCBs), and have similar neurotoxic effects. Research has correlated halogenated hydrocarbons, such as PCBs, with neurotoxicity. PBDEs are similar in chemical structure to PCBs, and it has been suggested that PBDEs act by the same mechanism as PCBs.
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The single contained three other versions of the song, titled as different tracks. "The Guns of Love Disastrous" is an instrumental version based around the tracks' various electronica-inspired elements, while the other instrumental, "The Ethers Tragic", is composed solely of its guitar parts. "The Beginning Is the End Is the Beginning" is a slower, less rock-oriented version with different lyrics for the verses, while the chorus is the same. This version appears on the Batman & Robin soundtrack as well.
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One study analyzed the plastic-derived chemical called polybrominated diphenyl ethers (PBDEs) in the stomachs of short-tailed shearwaters. It found that one-fourth of the birds had higher-brominated congeners that are not naturally found in their prey. However, the PBDE got into the birds' systems through plastic that was found in the stomachs of the birds. It is therefore not just the berska plastics that are being transferred through the food chain but the chemicals from the plastics as well.
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The United States Environmental Protection Agency (EPA) and others have shown that biosolids can contain measurable levels of synthetic organic compounds, radionuclides and heavy metals. EPA has set numeric limits for arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc but has not regulated dioxin levels. Contaminants from pharmaceuticals and personal care products and some steroids and hormones may also be present in biosolids. Substantial levels of persistent, bioaccumulative and toxic (PBT) polybrominated diphenyl ethers were detected in biosolids in 2001.
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Equatorial protection using TBDPS The increased stability towards acidic hydrolysis and nucleophilic species allows for the TBDPS groups in a substrate to be retained while other silyl ethers are removed. The TMS group may easily be removed in the presence of a TBDPS group by reaction with TsOH. The group is even more resistant to acid hydrolysis than the bulky TIPS. However, in the presence of a fluoride source such as TBAF or TAS-F, TIPS groups are more stable than TBDPS groups.
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Monomers for living cationic polymerization are electron- rich alkenes such as vinyl ethers, isobutylene, styrene, and N-vinylcarbazole. The initiators are binary systems consisting of an electrophile and a Lewis acid. The method was developed around 1980 with contributions from Higashimura, Sawamoto and Kennedy. Typically, generating a stable carbocation for a prolonged period of time is difficult, due to the possibility for the cation to be quenched by a β-protons attached to another monomer in the backbone, or in a free monomer.
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The Simmons–Smith reaction can be used to cyclopropanate simple alkenes without complications. Unfunctionalized achiral alkenes are best cyclopropanated with the Furukawa modification (see below), using Et2Zn and CH2I2 in 1,2-dichloroethane. Cyclopropanation of alkenes activated by electron donating groups proceed rapidly and easily. For example, enol ethers like trimethylsilyloxy-substituted olefins are often used because of the high yields obtained. 613x613px Despite the electron-withdrawing nature of halides, many vinyl halides are also easily cyclopropanated, yielding fluoro-, bromo-, and iodo-substituted cyclopropanes.
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More recently, glycol ethers (known as glymes) have come into use as carriers for the sodium naphthalene complex for PTFE etching. These glymes are ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), and tetraethylene glycol dimethyl ether (tetraglyme). Glymes pose minimal or no health risks to the user, and the solutions do not require special storage conditions. When using glyme- based etchants, it is recommended that the etching process be performed at moderately elevated temperatures, about 50 °C.
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Lacquer thinner, also known as cellulose thinner, is usually a mixture of solvents able to dissolve a number of different resins or plastics used in modern lacquer. Previously, lacquer thinners frequently contained alkyl esters like butyl or amyl acetate, ketones like acetone or methyl ethyl ketone, aromatic hydrocarbons like toluene, ethers such as glycol cellosolves, and/or alcohols. Modern lacquer thinners increasingly have to comply with low-VOC regulations. These formulations are often mostly acetone with small quantities of aromatic solvent.
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Cyclohexenone is a widely used building block in organic synthesis chemistry, as it offers many different ways to extend molecular frameworks. As an enone, cyclohexenone is easily adapted to Michael addition with nucleophiles (such as enolates or silyl enol ethers) or, it could be employed by a Diels-Alder reaction with electron-rich dienes. Furthermore, this compound reacts with organocopper compounds from 1,4-addition (Michael addition), or with Grignard reagents 1,2-addition, i.e., with attack of the nucleophile at the carbonyl carbon atom.
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In this molecule light triggers a trans-cis isomerization of the azo group which results in ring expansion. Thus in the trans form the crown binds preferentially to ammonium, lithium and sodium ions while in the cis form the preference is for potassium and rubidium (both larger ions in same alkali metal group). In the dark the reverse isomerization takes place. :MolecularSwitchShinkay1980 Shinkai employs this devices in actual ion transport mimicking the biochemical action of monensin and nigericin:Photoresponsive crown ethers. 2.
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J. Org. Chem. 1982 vol 47 pp3362-3364.Davidson, R. et al Enantiomeric recognition of organic ammonium salts by chiral crown ethers based on the pyridino-18-Crown-6 structure. J. Org. Chem. 1984 vol 49 pp353-357. Subsequent x- ray crystallographic resultsprovided a structural basis for the recognition.Davidson, R. et al Structures of the (4S,14S)-4,14-Dimethyl-3,6,9,12,15-pentaoxa-21-azabicyclo[15.3.1]heneicosa-1(21)17,19-triene-2,16-dione Complexes of R- and S-α-(1-Naphthyl)ethylammonium Perchlorate.
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Not all aromatic compounds can undergo Quelet reactions. For example, too highly halogenated aromatic compounds, aromatic compounds with nitro groups, and terphenyls cannot be used as reactants for Quelet reactions. Even for compounds that can undergo Quelet reactions, there sometimes exists other reactions that produce the same products in higher yields. The Quelet reaction can produce dangerous halomethyl ethers, gaseous and liquid compounds that are toxic to humans, and therefore is sometimes passed up for chloromethylations without these harmful biproducts.
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First discovered by Vincent L. Pecoraro and Myoung Soo Lah in 1989, metallacrowns are best described as inorganic analogues of crown ethers. To date, over 600 reports of metallacrown research have been published. Metallacrowns with sizes ranging from 12-MC-4 to 60-MC-20 have been synthesized. In 2013, the project "Metallacrowns: Metallacrown-based innovative materials and supramolecular devices" has been funded by the European Union Research Executive Agency as a Marie Curie IRSES International Research Staff Exchange Scheme.
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The reaction is thought to proceed through the formation of a diazo compound that is generated from a hydrazone salt. The diazo compound could then react with the boronic acid to produce the benzylboronic acid through a boronate intermediate. An alternate pathway consists of the formation of the benzylboronic acid via a zwitterionic intermediate, followed by protodeboronation of the benzylboronic acid under basic conditions, which results in the final reductive product. center This methodology has also been extended to heteroatom nucleophiles to produce ethers and thioethers.
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During research and development, pramocaine hydrochloride stood out among a series of alkoxy aryl alkamine ethers as an especially good topical local anesthetic agent. Pharmacologic study revealed it to be potent and of low acute and subacute toxicity, well tolerated by most mucous membranes and of a low sensitizing index in humans. Like other local anesthetics, pramocaine decreases the permeability of neuronal membranes to sodium ions, blocking both initiation and conduction of nerve impulses. Depolarization and repolarization of excitable neural membranes is thus inhibited, leading to numbness.
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The reaction mechanism centers on the formation of a free radical pair with lithium migrating from the carbon atom to the oxygen atom. The R radical then recombines with the ketyl.Wittig Rearrangement of Lithiated Allyl Aryl Ethers: A Mechanistic Study Sven Strunk, Manfred Schlosser European Journal of Organic Chemistry Volume 2006, Issue 19 , pp. 4393–97 The 1,2-Wittig rearrangement reaction mechanism The alkyl group migrates in the order of thermodynamical stability methyl < primary alkyl < secondary alkyl < tertiary alkyl, this is in line with the radical mechanism.
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Tellurides also describe a class of organotellurium compounds formally derived from Te2−. An illustrative member is dimethyl telluride, which results from the methylation of telluride salts: :2 CH3I + Na2Te → (CH3)2Te + 2 NaI Dimethyl telluride is formed by the body when tellurium is ingested. Such compounds are often called telluroethers because they are structurally related to ethers with tellurium replacing oxygen, although the length of the C–Te bond is much longer than a C–O bond. C–Te–C angles tend to be closer to 90°.
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Since American kestrels are carnivores, toxic chemical runoff ingested by their prey can concentrate at high levels in their blood. Wild kestrels are subject to immunomodulation, or an altered immune response, to polybrominated diphenyl ethers (PBDEs), a group of industrial flame retardants that may leach from factories into the environment. When PBDEs accumulate in body tissues of kestrels, the T-cell mediated immune response decreases in efficiency. As a result, kestrels that ingest PBDEs may not respond sufficiently to viruses or other invading microorganisms.
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Meyer compared the potency of many agents, defined as the reciprocal of the molar concentration required to induce anaesthesia in tadpoles, with their olive oil/water partition coefficient. He found a nearly linear relationship between potency and the partition coefficient for many types of anaesthetic molecules such as alcohols, aldehydes, ketones, ethers, and esters. The anaesthetic concentration required to induce anaesthesia in 50% of a population of animals (the EC50) was independent of the means by which the anaesthetic was delivered, i.e., the gas or aqueous phase.
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The Furukawa Modification involves the replacement of the zinc-copper couple with dialkyl zinc, the most active of which was found to be Et2Zn. The modification was proposed in 1968 as a way to turn cationically polymerizable olefins such as vinyl ethers into their respective cyclopropanes. It has also been found to be especially useful for the cyclopropanation of carbohydrates, being far more reproducible than other methods. Like the unmodified reaction, the Furukawa- modified reaction is stereospecific, and is often much faster than the unmodified reaction.
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The Selexol solvent is a mixture of the dimethyl ethers of polyethylene glycol. Selexol is a physical solvent, unlike amine based acid gas removal solvents that rely on a chemical reaction with the acid gases. Since no chemical reactions are involved, Selexol usually requires less energy than the amine based processes. However, at feed gas pressures below about 300 psia(2.07 MPa), the Selexol solvent capacity (in amount of acid gas absorbed per volume of solvent) is reduced and the amine based processes will usually be superior.
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Ball-and-stick model of the bis(12-crown-4)lithium cation Like other crown ethers, 12-crown-4 complexes with alkali metal cations. The cavity diameter of 1.2-1.5 Å gives it a high selectivity towards the lithium cation (ionic diameter 1.36 Å) Its point group is S4. The dipole moment of 12-crown-4 varies with solvent and temperature. At 25 °C, the dipole moment of 12-crown-4 was determined as 2.33 ± 0.03 D in cyclohexane and 2.46 ± 0.01 D in benzene.
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18-crown-6 can be synthesized from using potassium ion as the template cation Illustrations of a. metal-organic frameworks and b. supramolecular coordination complexes As studied in coordination chemistry, metal ions (usually transition metal ions) exist in solution bound to ligands, In many cases, the coordination sphere defines geometries conducive to reactions either between ligands or involving ligands and other external reagents. A well known metal-ion-templating was described by Charles Pederson in his synthesis of various crown ethers using metal cations as template.
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N-hydroxyphthalimide forms strongly colored, mostly yellow or red salts with alkali and heavy metals, ammonia and amines. Hydrolysis of N-hydroxyphthalimide by the addition of strong bases produces phthalic acid monohydroxamic acid by adding water across one of the carbon-nitrogen bonds. N-hydroxyphthalimide ethers, on the other hand, are colorless and provide O-alkylhydroxylamines by alkaline hydrolysis or cleavage through hydrazine hydrate. The "phthalylhydroxylamine" reported by Cohn was known to have a molecular formula of but the exact structure was not known.
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Hexafluoroisopropanol, commonly abbreviated HFIP, is the organic compound with the formula (CF3)2CHOH. This fluoroalcohol finds use as solvent and synthetic intermediate. It appears as a colorless, volatile liquid that is characterized by a strong, pungent odor. As a solvent hexafluoro-2-propanol is polar and exhibits strong hydrogen bonding properties enabling it to dissolve substances that serve as hydrogen-bond acceptors, such as amides and ethers. (CF3)2CHCOH is classified as a hard Lewis acid and its acceptor properties are discussed in the ECW model.
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Other base stocks are used for specialty applications, such as for fire resistance and extreme temperature applications. Some examples include: glycol ethers, organophosphate ester, polyalphaolefin, propylene glycol, and silicone oils. NaK-77, a eutectic alloy of sodium and potassium, can be used as a hydraulic fluid in high-temperature and high-radiation environments, for temperature ranges of 10 to 1400 °F (-12 to 760 °C). Its bulk modulus at 1000 °F (538 °C) is 310,000 psi (2.14 GPa), higher than of a hydraulic oil at room temperature.
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Certain manganese amides of the type RR1NMnR2 are used for the deprotonation of ketones forming manganese enolates. Just like lithium enolates they can further react with silyl chlorides to silyl enol ethers, with alkyl halides in alpha-alkylation and with aldehydes and ketones to beta-keto-alcohols. Manganese enolates can also be obtained by transmetalation of manganese halides with Li, Mg, K or Na enolates. Manganese halides are catalysts in several homo- and crosscoupling reactions involving stannanes and Grignards in which organomanganese intermediates play a part.
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Polyphenyl ethers (PPEs) possess good optical clarity, a high refractive index, and other beneficial optical properties. Because of these, PPEs have the ability to meet the rigorous performance demands of signal processing in advanced photonics systems. Optical clarity of PPEs resembles that of the other optical polymers, that is, they have refractive indices of between 1.5 and 1.7 and provide good propagation of light between approximately 400 nm and 1700 nm. Close refractive index (RI) matching between materials is important for proper propagation of light through them.
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A variety of supramolecular polymers can be synthesized by using monomers with host-guest complementary binding motifs, such as crown ethers/ammonium ions, cucurbiturils/viologens, calixarene/viologens, cyclodextrins/adamantane derivatives, and pillar arene/imidazolium derivatives [30–33]. When the monomers are “heteroditopic”, supramolecular copolymers results, provided the monomers does not homopolymerize. Akira Harada was one of the firstwhorecognize the importance of combining polymers and cyclodextrins. Feihe Huang showed an example of supramolecular alternating copolymer from two heteroditopic monomers carrying both crown ether and ammonium ion termini.
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Metallacrown nomenclature has been developed to mimic the nomenclature of crown ethers, which are named by the total number of atoms in the ring, followed by "C" for "crown," and the number of oxygen atoms in the ring. For example, 12-crown-4 or 12-C-4 describes Figure 2a. When naming metallacrowns, a similar format is followed. However, the C becomes "MC" for "metallacrown" and the "MC" is followed by the ring metal, other heteroatom, and the ligand used to make the metallacrown.
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Semipermeable membrane devices (SPMDs) passively sample nonpolar organic contaminants with a log octanol-water partition coefficient (Kow) value greater than 3. Examples of these types of chemicals include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), chlorinated pesticides, dioxins, and furans. SPMDs are composed of sealed plastic tubing filled with triolein, in which nonpolar organics are very soluble and which serves as a representation of the fatty tissues of aquatic organisms. The tubing is then weaved between metal rods and enclosed in a metal cage.
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Cellulose fibers () are fibers made with ethers or esters of cellulose, which can be obtained from the bark, wood or leaves of plants, or from other plant- based material. In addition to cellulose, the fibers may also contain hemicellulose and lignin, with different percentages of these components altering the mechanical properties of the fibers. The main applications of cellulose fibers are in the textile industry, as chemical filters, and as fiber-reinforcement composites, due to their similar properties to engineered fibers, being another option for biocomposites and polymer composites.
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Other modifications to these types of systems are free radical assisted cationic polymerization. In this case, a free radical is formed from another species in solution that reacts with the photoinitiator in order to start polymerization. Although there are a diverse group of compounds activated by cationic photoinitiators, the compounds that find most industrial uses contain epoxides, oxetanes, and vinyl ethers. One of the advantages to using cationic photopolymerization is that once the polymerization has begun it is no longer sensitive to oxygen and does not require an inert atmosphere to perform well.
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Common choices for derivatization include N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and mixture of pyridine and bis(trimethylsilyl)trifluoroacetamide (BSTFA), both of which aim to convert the free hydroxyl groups to trimethylsilyl ethers, making the molecules more non-polar and thus more suitable for GC/MS analysis. In GC/MS, taraxerol has a signature peak with a mass-to-charge ratio (m/z) of 204. Total ion current traces of R. racemosa saponified leaf extracts, showing taraxerol-OTMS (6) with β-amyrin methyl-ether (7) and germanicol-OTMS (8). Adapted from Versteegh et al. (2004).
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Aryl and heteroaryl organolithium reagents undergo efficient electrophilic amination under copper (I) catalyzed condition mediated by recoverable silicon reagents, termed siloxane transfer agents. :none The scope of sp-centered carbanions is limited to alkynylcuprates. Enolates and silyl enol ethers, the most widely used class of carbon nucleophiles in electrophilic amination reactions, participate in amination, adization and hydrazination reactions. The primary application of alkylmetal reagents in electrophilic amination reactions is the synthesis of hindered amines, many of which are difficult to prepare through nucleophilic displacement with an alkyl halide (nucleophilic amination).
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The musicians making up The Minus 5 overlapped with the auxiliary touring members of R.E.M. and Tuatara; the musicians recorded The Lonesome Death of Buck McCoy alongside Mark Eitzel's West. The opportunity to record and tour with the material spurred Scott McCaughey to finish off songs that Peter Buck had started writing two years prior. The revolving door of performers supported all their releases (including Tuatara's Breaking the Ethers) with The Magnificent Seven Vs. the United States tour in 1997. This album was the first release from Hollywood Records imprint Malt Records.
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The chemical make up of stomach oil varies from species to species and between individuals, but almost always contains both wax esters and triglycerides. Other compounds found in stomach oil include glycerol ethers, pristane and squalene. Stomach oil has low viscosity and will solidify into a hard wax if allowed to cool. It was once thought that stomach oil was a secretion of the proventriculus, but it is now known to be a residue of the diet created by digestion of the prey items such as krill, squid, copepods and fish.
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2008, 73, 1. Organosilanes offer the advantage of greater robustness to a wide array of reaction conditions than allyl compounds of more electropositive metals, and do not spontaneously undergo allylic rearrangement or epimerization. Additionally, organosilanes are rarely toxic and their reactions can be easily tracked by NMR spectroscopy (because of distinctive changes in the position of resonance of the methyl groups attached to silicon as addition occurs). Reactions of allylsilanes are similar in many respects to reactions of silyl enol ethers—in fact, allylsilanes can be used as masked enolate equivalents.
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As long as the nucleophilicity of the alkyl group does not lead to side reactions, catalytic amounts of Lewis acid are sufficient for many ene reactions with reactive enophiles. Nonetheless, the amount of Lewis acid can widely vary, as it largely depends on the relative basicity of the enophile and the ene adduct. In terms of solvent choice for the reactions, the highest rates are usually achieved using halocarbons as solvents; polar solvents such as ethers are not suitable, as they would complex to the Lewis acid, rendering the catalyst inactive.
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The radical-ketyl pair is short lived and due to a solvent cage effect some isomerizations take place with retention of configuration. With certain allyl aryl ethers a competing reaction takes place. The reaction of allyl phenyl ether 1 with sec- butyllithium at −78 °C gives the lithiated intermediate 2 which on heating to −25 °C only shows the rearranged product 5 but not 4 after trapping the lithium alkoxide with trimethylsilyl chloride. This result rules out a radical-ketyl intermediate 3a in favor of the Meisenheimer complex 3b.
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This transformation is proposed to occur by oxidation of the amine to the aminium radical cation by the excited photocatalyst. This is followed by hydrogen atom transfer to a superstoichimetric oxidant, such as trichloromethyl radical (CCl3 to form the iminium ion). The iminium ion is then quenched by reaction with a nucleophile. Related transformations of amines with a wide variety of other nucleophiles have been investigated, such as cyanide (Strecker reaction), silyl enol ethers (Mannich reaction), dialkylphosphates, allyl silanes (aza-Sakurai reaction), indoles (Friedel-Crafts reaction), and copper acetylides.
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Potassium superoxide is a strong oxidant, able to convert oxides into peroxides or molecular oxygen. Hydrolysis gives oxygen gas, hydrogen peroxide and potassium hydroxide: :2 + 2 → 2 KOH + + Potassium hydroxide (KOH) absorbing carbon dioxide produces carbonates: :2 KOH + → K2CO3 \+ H2O :KOH + → KHCO3 Combining these two reactions produces: :4 + 2 → 2 K2CO3 \+ 3 :4 + 4 + 2 H2O → 4 KHCO3 \+ 3 Potassium superoxide finds only niche uses as a laboratory reagent. Because it reacts with water, is often studied in organic solvents. Since the salt is poorly soluble in nonpolar solvents, crown ethers are typically used.
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In organic chemistry a methylthiomethyl (MTM) ether is a protective group for hydroxyl groups. Hydroxyl groups are present in many chemical compounds and they must be protected during oxidation, acylation, halogenation, dehydration and other reactions to which they are susceptible. Many kinds of protective groups for hydroxyl groups have been developed and used in organic chemistry, but the number of protective groups for tertiary hydroxyl groups, which are susceptible to acid-catalyzed dehydration, is still small because of their poor reactiveness. They can be easily protected with MTM ethers and recovered in good yield.
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A slightly milder set of conditions uses cyclohexyl iodide (CyI, 10.0 equiv) in N,N-dimethylformamide to generate a small amount of hydrogen iodide in situ. Boron tribromide, which can be used at room temperature or below, is a more specialized reagent for the demethylation of aryl methyl ethers. The mechanism of ether dealkylation proceeds via the initial reversible formation of a Lewis acid-base adduct between the strongly Lewis acidic BBr3 and the Lewis basic ether. This Lewis adduct can reversibly dissociate to give a dibromoboryl oxonium cation and Br–.
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All people are exposed to chemicals with estrogenic effects in their everyday life, because endocrine disrupting chemicals are found in low doses in thousands of products. Chemicals commonly detected in people include DDT, polychlorinated biphenyls (PCB's), bisphenol A (BPA), polybrominated diphenyl ethers (PBDE's), and a variety of phthalates. In fact, almost all plastic products, including those advertised as "BPA free", have been found to leach endocrine-disrupting chemicals. In a 2011, study it was found that some "BPA- free" products released more endocrine active chemicals than the BPA- containing products.
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Chemical structure of ceteareth-n, where n is variable from 2 to 100 and m is 15 or 17 The INCI names ceteareth-n (where n is a number) refer to polyoxyethylene ethers of a mixture of high molecular mass saturated fatty alcohols, mainly cetyl alcohol (m = 15) and stearyl alcohol (m = 17). The number n indicates the average number of ethylene oxide residues in the polyoxyethylene chain. These compounds are non-ionic surfactants that work by attracting both water and oil at the same time, frequently used as emulsifiers in soaps and cosmetics.
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Some of the most important transformations include the hydrogenation of ketones to alcohols or ethers (the latter product forming in the presence of alcohols and acids) and the reduction of nitro compounds to amines. However, reductions of alkenes can be performed with Adam's catalyst in the presence of nitro groups without reducing the nitro group. When reducing nitro compounds to amines, platinum catalysts are preferred over palladium catalysts to minimize hydrogenolysis. The catalyst is also used for the hydrogenolysis of phenyl phosphate esters, a reaction that does not occur with palladium catalysts.
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Alkyl and aryl derivatives of sodium and potassium tend to react with air. They cause the cleavage of ethers, generating alkoxides. Unlike alkyllithium compounds, alkylsodiums and alkylpotassiums cannot be made by reacting the metals with alkyl halides because Wurtz coupling occurs: :RM + R'X → R–R' + MX As such, they have to be made by reacting alkylmercury compounds with sodium or potassium metal in inert hydrocarbon solvents. While methylsodium forms tetramers like methyllithium, methylpotassium is more ionic and has the nickel arsenide structure with discrete methyl anions and potassium cations.
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At higher temperatures, ethanol will dehydrate to form ethylene. The reaction to make diethyl ether is reversible, so eventually an equilibrium between reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture before it reverts to ethanol, taking advantage of Le Chatelier's principle. Another reaction that can be used for the preparation of ethers is the Williamson ether synthesis, in which an alkoxide (produced by dissolving an alkali metal in the alcohol to be used) performs a nucleophilic substitution upon an alkyl halide.
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Nonactin is known for its ability to form complexes with alkali cations, most notably potassium and sodium. In general, nonactin (and other members of the nactin family) exhibits binding preferences for some ions over others. This ion selectivity is seen in other macrocyclic ligands, such as the cyclic ionophore valinomycin, which is also an antibiotic, and crown ethers. Although nonactin (and all nactins) exhibits an especially high cation selectivity for potassium ions over sodium ions or rubidium ions, it exhibits the highest selectivity for ammonium ions and thallium ions.
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The oxygen atoms are well situated to coordinate with a cation located at the interior of the ring, whereas the exterior of the ring is hydrophobic. The resulting cations often form salts that are soluble in nonpolar solvents, and for this reason crown ethers are useful in phase transfer catalysis. The denticity of the polyether influences the affinity of the crown ether for various cations. For example, 18-crown-6 has high affinity for potassium cation, 15-crown-5 for sodium cation, and 12-crown-4 for lithium cation.
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November 2009 (a bis-epoxide) is formed, which can be used as a replacement for the analog bisphenol A bis- epoxide. Isosorbide bis-glycidyl ether can be crosslinked to a thermosetting epoxy resins with suitable curing agents, such as polyamines or cyclic acid anhydrides. These resins are used as adhesives, paints or coatings for food cans.Press Release NEWARK, Feb 24 2010: NJIT Patent May Be Able To Replace BPA; Make Consumer Products Safer Furthermore, polyoxazolidones are described which can be obtained by reaction of isosorbide diglycidyl ethers with diisocyanates.
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The thiol-ene reaction (and analogous thiol-yne reaction) have extensively been used in generating reactive intermediates for the cyclization of unsaturated substrates. Radical hydrothiolation of an unsaturated functional group indirectly generates a carbon-centered radical, which can then cyclize intramolecularly onto alkenes, oxime ethers, isocyanides, cyano groups, and aromatic rings. The use of thiyl radicals as initiators of cyclization has been employed in the synthesis of a number of natural products, including aplysins, α-kainic acid, asperparalines, and alkaloids such as narciclasine and lycoricidine. The synthesis of kainic acid via thiyl radical-induced cyclization.
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In addition to the adsorbents, oxidizers, surfactants, and disinfectants listed above, ingredients in air fresheners can include fragrances, aerosol propellants, preservatives, and solvents such as mineral oil or 2-butoxyethanol and other glycol ethers. As fragrances, air freshener preparations often include terpenes such as limonene. A report issued in 2005 by the Bureau Européen des Unions de Consommateurs (BEUC) found that many air freshener products emit allergens and toxic air pollutants including benzene, formaldehyde, terpenes, styrene, phthalate esters, and toluene.January 2005, BEUC report: Emission of chemicals by air fresheners.
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An important aspect of the Simmons–Smith reaction that contributes to its wide usage is its ability to be used in the presence of many functional groups. Among others, the haloalkylzinc-mediated reaction is compatible with alkynes, alcohols, ethers, aldehydes, ketones, carboxylic acids and derivatives, carbonates, sulfones, sulfonates, silanes, and stannanes. However, some side reactions are commonly observed. Most side reactions occur due to the Lewis- acidity of the byproduct, ZnI2. In reactions that produce acid-sensitive products, excess Et2Zn can be added to scavenge the ZnI2 that is formed, forming the less acidic EtZnI.
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In the field of organometallic chemistry, the X-ray structure of ferrocene initiated scientific studies of sandwich compounds, while that of Zeise's salt stimulated research into "back bonding" and metal-pi complexes. Finally, X-ray crystallography had a pioneering role in the development of supramolecular chemistry, particularly in clarifying the structures of the crown ethers and the principles of host–guest chemistry. X-ray diffraction is a very powerful tool in catalyst development. Ex-situ measurements are carried out routinely for checking the crystal structure of materials or to unravel new structures.
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Detectable compound classes in order of decreasing sensitivity include: aromatics and alkyl iodides; olefins, sulfur compounds, amines, ketones, ethers, alkyl bromides and silicate esters; organic esters, alcohols, aldehydes and alkanes; H2S, NH3, PH3 and organic acids. There is no response to standard components of air or to mineral acids. Major advantages of PIDs are their excellent sensitivity and simplicity of use; the main limitation is that measurements are not compound-specific. Recently PIDs with pre-filter tubes have been introduced that enhance the specificity for such compounds as benzene or butadiene.
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ISAF brings together technologists, technical experts, technology providers and executives in fields pertaining to the alcohol fuel industry, who share their ideas and consider solutions to the challenges ahead. ISAF discusses substitute energy sources like alcohol fuels and other alternative fuels like methanol, ethers, etc. ISAF furthers the cause of research, development and utilization of alcohol fuels to accelerate the exploitation of clean alternate fuels for vehicles and to reduce environmental pollution both from industrial and motor sources. Reports and handbooks of the ISAF are frequently cited in scholarly articles and treatises about methanol and similar fuels.
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Crown ether coordinating a potassium ion Charles John Pedersen (October 3, 1904 – October 26, 1989) was an American organic chemist best known for describing methods of synthesizing crown ethers during his entire 42-year career as a chemist for DuPont at DuPont Experimental Station in Wilmington, Delaware and at DuPont's Jackson Laboratory in Deepwater, New Jersey. Often associated with Reed McNeil Izatt, Pedersen also shared the Nobel Prize in Chemistry in 1987 with Donald J. Cram and Jean-Marie Lehn. He is the only Nobel Prize laureate born in Korea other than Peace Prize laureate Kim Dae- jung.
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Tricin synthase (, ROMT-17, ROMT-15, HvOMT1, ZmOMT1) is an enzyme with systematic name S-adenosyl-L-methionine:tricetin 3',5'-O-dimethyltransferase. This enzyme catalyses the following chemical reaction : 2 S-adenosyl-L- methionine + tricetin \rightleftharpoons 2 S-adenosyl-L-homocysteine + 3',5'-O-dimethyltricetin (overall reaction) :(1a) S-adenosyl-L-methionine + tricetin \rightleftharpoons S-adenosyl-L-homocysteine + 3'-O-methyltricetin :(1b) S-adenosyl-L-methionine + 3'-O-methyltricetin \rightleftharpoons S-adenosyl-L-homocysteine + 3',5'-O-dimethyltricetin The enzymes from Oryza sativa (ROMT-15 and ROMT-17) catalyses the stepwise methylation of tricetin to its 3'-mono- and 3',5'-dimethyl ethers.
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Charles J. Pedersen shared the 1987 Nobel Prize in chemistry for his methods of synthesizing crown ethers. In 2008, biochemist Roger Tsien won the Nobel in Chemistry for his work on engineering and improving the green fluorescent protein (GFP) that has become a standard tool of modern molecular biology and biochemistry. Venkatraman Ramakrishnan won the prize in Chemistry "for studies of the structure and function of the ribosome". Ching W. Tang was the inventor of the Organic light-emitting diode and Organic solar cell and was awarded the 2011 Wolf Prize in Chemistry for this achievement.
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IA-Mass identifies the presence of bromine (PBB, PBDE, and some others), but cannot characterize all the BFRs present in the plastic matrix. In February 2009, the Institute for Reference Materials and Measurements (IRMM) released two certified reference materials (CRMs) to help analytical laboratories better detect two classes of flame retardants, namely polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs). The two reference materials were custom made to contain all relevant PBDEs and PBBs at levels close to the legal limit set out in the RoHS Directive of 1 g/kg for the sum of PBBs and PBDEs.
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Compared with LERs (liquid epoxy resins) they have very low viscosities. If, however, they are used in larger proportions as reactive diluents, this often leads to reduced chemical and thermal resistance and to poorer mechanical properties of the cured epoxides. Large scale epoxidized vegetable oils such as epoxidized soy and lens oils are used to a large extent as secondary plasticizers and cost stabilizers for PVC. Aliphatic glycidyl epoxy resins of low molar mass (mono-, bi- or polyfunctional) are formed by the reaction of epichlorohydrin with aliphatic alcohols or polyols (glycidyl ethers are formed) or with aliphatic carboxylic acids (glycidyl esters are formed).
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The invention of LiS batteries dates back to the 1960s, when Herbert and Ulam patented in 1962, a primary battery employing lithium or lithium alloys as anodic material, sulfur as cathodic material and an electrolyte composed of aliphatic saturated amines.US 3043896A A few years later the technology was improved by the introduction of organic solvents as PC, DMSO and DMF obtaining a 2.35-2.5 V battery. By the end of the 1980s a rechargeable LiS battery was demonstrated employing ethers, in particular DOL, as the solvent for the electrolyte. Thanks to scientific improvements in the field, the potential of LiS batteries was highlighted.
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A common application is the conversion of ketones and aldehydes to silyl enol ethers. The stereoselective synthesis of seven benzylated proanthocyanidin trimers (epicatechin-(4β-8)-epicatechin-(4β-8)-epicatechin trimer (procyanidin C1), catechin-(4α-8)-catechin-(4α-8)-catechin trimer (procyanidin C2), epicatechin-(4β-8)-epicatechin-(4β-8)-catechin trimer and epicatechin-(4β-8)-catechin-(4α-8)-epicatechin trimer derivatives) can be achieved with TMSOTf-catalyzed condensation reaction, in excellent yields. Deprotection of (+)-catechin and (−)-epicatechin trimers derivatives gives four natural procyanidin trimers in good yields.Efficient Stereoselective Synthesis of Proanthocyanidin Trimers with TMSOTf-Catalyzed Intermolecular Condensation.
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István Ledneczki, Peter Forgo, Árpad Molnár (2007), Fused polycyclic hydrocarbons through superacid-induced cyclialkylation of aromatics. Catalysis Letters, volume 119, pages 296–303. TMTHF undergoes photolysis by UV; in aqueous solution, the products are mainly methane, ethane, and 2-hydroxy-2,5,5-trimethyltetrahydrofuran. Knut Hildebrand, Heinz- Peter Schuchmann, Clemens Von Sonntag (1989), The vacuum UV photolysis of aqueous solutions of two saturated ditertiary ethers: A product and CIDNP study, Journal of Photochemistry and Photobiology, Series A: Chemistry, volume 48, pages 219–232. The dehydration of TMTHF yields alkenes like 2,5-dimethyl-2,4-hexadiene and 2,5-dimethyl-1,5-hexadiene.
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Heteroatom additions to rings can occur through ring expansions if not they are not done through de-novo ring synthesis. These introductions are primarily ring expansions because they often take place through migration/insertion pathways similar to those mentioned above for carbon. Examples include high impact applications of the Beckmann rearrangement (for introduction of nitrogen into codeine) and the Baeyer-Villiger oxidation (introduction of oxygen to cage-annulated ethers) in synthesis. Both occur with the expulsion of a leaving group as the alkyl group migrates onto the exocyclic heteroatom, which is strikingly similar to the pinacol type rearrangement.
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Isosorbide ethers (and in particular the simplest representative, 2,5-dimethylisosorbide, abbreviated DMI), are increasingly used as a renewable solvent for cosmetic and pharmaceutical preparations,Grant Industries: About Dimethyl Isosorbide as an electrolyte additive for lithium- ion accumulatorsUS-Patentanmeldung US 2010/0183913 Lithium cell with iron disulfide cathode and improved electrolyte, invent1: M. Sliger et al., assign1: The Procter & Gamble Co., veröffentlicht am 22. Juli 2010 [18] and as a fuel additive for diesel.US-Patentanmeldung US 2010/0064574A1 Diesel cycle fuel compositions containing dianhydrohexitols and related products, invent1: R.M. de Almeida, C.R. Klotz Rabello, assign1: Petróleo Brasileiro S.A.-Petrobras, veröffentlicht am 18.
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2-Methoxyethanol, or methyl cellosolve, is an organic compound with formula that is used mainly as a solvent. It is a clear, colorless liquid with an ether-like odor. It is in a class of solvents known as glycol ethers which are notable for their ability to dissolve a variety of different types of chemical compounds and for their miscibility with water and other solvents. It can be formed by the nucleophilic attack of methanol on protonated ethylene oxide followed by proton transfer: : + → + 2-Methoxyethanol is used as a solvent for many different purposes such as varnishes, dyes, and resins.
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Due to living in frigid depths, the sleeper shark's liver oil does not contain squalene, which would solidify into a dense, nonbuoyant mass. Instead, the low-density compounds in the sharks' liver are diacylglyceryl ethers and triacylglycerol, which maintain their fluidity even at the lowest temperatures. Also, they store very little urea in their skin (like many deep sea sharks), but like other elasmobranchs, have high concentrations of urea and trimethylamine oxide (nitrogenous waste products) in their tissues as osmoprotectants and to increase their buoyancy. Trimethylamine oxide also serves to counteract the protein-destabilizing tendencies of urea and pressure.
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Other electrolytes researched include borohydrides, phenolates, alkoxides, amido based complexes (e.g. based on hexamethyldisilazane), carborane salts, fluorinated alkoxyborates, a Mg(BH4)(NH2) solid state electrolyte, and gel polymers containing Mg(AlCl2EtBu)2 in tetraglyme/PVDF. The current wave of interest in magnesium- metal batteries started in 2000, when an Israeli group reported reversible magnesium plating from mixed solutions of magnesium chloride and aluminium chloride in ethers, such as THF. The primary advantage of this electrolyte is a significantly larger positive limit of the voltage window (and, thus, a higher battery voltage) than of the previously reported Mg plating electrolytes.
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Fabuloso multipurpose cleaner and generic surface cleaners All- purpose cleansers contain mixtures of anionic and nonionic surfactants, polymeric phosphates or other sequestering agents, solvents, hydrotropic substances, polymeric compounds, corrosion inhibitors, skin-protective agents, and sometimes perfumes and colorants. Aversive agents, such as denatonium, are occasionally added to cleaning products to discourage animals and small children from consuming them. Some cleaners contain water-soluble organic solvents like glycol ethers and fatty alcohols, which ease the removal of oil, fat and paint. Disinfectant additives include quaternary ammonium compounds, phenol derivatives, terpene alcohols (pine oil), aldehydes, and aldehyde-amine condensation products.
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Ed Anderson attended Magdalen College, Oxford, and graduated from the University with bachelor of arts degree in Chemistry in 1997, having completed his research project on gold nanoparticles under the supervision of Harry Anderson. Between 1997 and 2001, he completed a doctorate at Gonville and Caius College in the University of Cambridge under the supervision of Andrew Holmes. His research focused on the applications and synthesis of medium-ring lactones and ethers. He took up a two-year post-doctoral research position assisting Erik J. Sorensen at The Scripps Research Institute and helped to synthesise furanosteriod viridin.
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For example, with the Wulff–Dötz reaction an alkyne, carbon monoxide, and a chromium carbene are combined to form a chromium half-sandwich complex and the phenol ligand can be isolated by mild CAN oxidation. :700px CAN is used to cleave para-methoxybenzyl and 3,4-dimethoxybenzyl ethers, which are protecting groups for alcohols.Boons, Geert-Jan.; Hale, Karl J. (2000). Organic Synthesis with Carbohydrates (1st ed.) Sheffield, England: Sheffield Academic Press. pp.33Kocienski, Phillip J. (1994). Protecting Groups Stuttgart, New York Georg Thieme Verlag. pp 8-9, 52-54 Two equivalents of CAN are required for each equivalent of para-methoxybenzyl ether.
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As Pedersen began working on problems as a new chemist, he was free to work on whatever problems fascinated him and he quickly became interested in oxidative degradation and stabilization of substrate. Pedersen's papers and work expanded beyond this, however it was a major influence to his eventual Nobel Prize awarded research. Retiring at the age of 65, his work resulted in 25 papers and 65 patents, and in 1967, he published two works describing the methods of synthesizing crown ethers (cyclic polyethers). The donut-shaped molecules were the first in a series of extraordinary compounds that form stable structures with alkali metal ions.
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Crude MCHM is a chemical foam used to wash coal and remove impurities that contribute to pollution during combustion. The "do-not- use" advisory for drinking water from West Virginia American Water's system began to be gradually lifted by West Virginia state officials on January 13 based upon "priority zones." On Tuesday, January 14, the company revealed that the tank, which leaked about 7,500 gallons into the ground by the Elk River, had also contained a mixture of glycol ethers known as PPH, with a similar function as MCHM. The chemical spill was the third chemical accident to occur in the Kanawha River Valley within the last five years.
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Most effort involved aprotic materials, which consist of a lithium metal anode, a liquid organic electrolyte and a porous carbon cathode. The electrolyte can be made of any organic liquid able to solvate lithium salts such as , , , and ), but typically consisted of carbonates, ethers and esters. The carbon cathode is usually made of a high- surface-area carbon material with a nanostructured metal oxide catalyst (commonly or ). A major advantage is the spontaneous formation of a barrier between anode and electrolyte (analogous to the barrier formed between electrolyte and carbon–lithium anodes in conventional Li-ion batteries) that protects the lithium metal from further reaction with the electrolyte.
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Like the morphine metabolite morphine-6-glucuronide, 6-position branches (esters or ethers) of morphine bind to the otherwise unagonized human mu receptor subtype mu-3 (or μ3); as well as the 6-acetylmorphine metabolite of heroin this includes heterocodeine. The relative strength of heterocodeine to codeine has been published as 50, 72, 81, 88, 93, 96, and 108 x. It is not mentioned specifically in the Controlled Substances Act 1970 but is a Schedule II controlled substance as an analogue of morphinan or morphine under the morphine structure rules of the Analogues Act; in other countries it is usually controlled as a strong opioid. Homocodeine is a synonym for pholcodine.
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COMMISSION DECISION of 13 October 2005 amending for the purposes of adapting to the technical progress the Annex to Directive 2002/95/EC of the European Parliament and of the Council on the restriction of the use of certain hazardous substances in electrical and electronic equipment (2005/717/EC). Official Journal of the European Union 15.10.2005.COMMISSION DECISION of 24 September 2010 amending, for the purposes of adapting to scientific and technical progress, the Annex to Directive 2002/95/EC of the European Parliament and of the Council as regards exemptions for applications containing lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls or polybrominated diphenyl ethers (2010/571/EU).
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In the Flat Earth series, the world is a flat square, with area approximating that of the Earth. The Flat Earth floats amid formless chaos; the sun and moon rise out of the chaos in the east, travel across the upper ethers of the world, and then descend back into chaos in the west. What happens to the sun and moon while in chaos is not clear. The cosmology of the books is composed of four "layers": the Underearth, which is the realm of demons; the Flat Earth itself; the Upperearth, which is the realm of the gods; and the Innerearth, the realm of the dead.
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Since the discovery of crown ethers and cryptands by Pederson, Cram and Lehn (for which they received the Nobel Prize in 1987), the significance of molecules containing the repeat units -CH2-CH2-O- as coordinating ligands for metal cations has been recognised. By combining salts and polyethers such as polyethylene oxide (-CH2-CH2-O-)n, it is possible to synthesise thousands of metal-polyether complexes, alternatively known as polymer electrolytes. Such materials are co-ordination compounds in the solid state and support ionic conductivity. For 30 years it was believed that ionic conductivity was confined to amorphous polymers above Tg and that crystalline polymers were insulators.
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A reaction characteristic of Ph2Se2 is its reduction: :Ph2Se2 \+ 2 Na -> 2 PhSeNa PhSeNa is a useful nucleophile used to introduce the phenylselenyl group by nucleophilic substitution of alkyl halides, alkyl sulfonates (mesylates or tosylates) and epoxides. The example below was taken from a synthesis of morphine. :600px Another characteristic reaction is chlorination: :Ph2Se2 \+ Cl2 -> 2 PhSeCl PhSeCl is a powerful electrophile, used to introduce PhSe groups by reaction with a variety of nucleophiles, including enolates, enol silyl ethers, Grignard reagents, organolithium reagents, alkenes and amines. In the sequence below (early steps in the synthesis of Strychnofoline), a PhSe group is introduced by reaction of a lactam enolate with PhSeCl.
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These markers are generally used on hard, non-porous surfaces, because instead of staining they form a surface layer that can be removed by high pressure cleaning or paint thinners. Organic solvents such as acetone, xylene, or toluene. Isopropyl alcohol, ethanol and ethyl acetate are preferred cleaners when used indoors, as their fumes are much less hazardous than toluene and xylene, the main components of paint thinner, or longer-chain hydrocarbons found in mineral spirits. Other common non-polar solvents include benzene, turpentine and other terpenes (which constitute essential oils of many plants with strong scents), most ethers, chloroform and dichloromethane, hydrocarbon fuels, and diacetone alcohol, among many others.
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Metallacrowns and related organic crown ethers a) 12-crown-4 b)12-MCFe(III)N-4 c) 15-crown-5 d) 15-MCCu(II)N-5 Metallacrowns are a class of cyclic compounds that contain metal ions and non- metals in repeating units. Vincent L. Pecoraro and Myoung Soo Lah reported the first metallacrown in 1989 and these compounds have since grown into their own field of research with numerous new applications. One of the most interesting aspects of these compounds is their diversity. The ring size can be changed by incorporating new ligands or different metals into the frame work, which leads to the internal cavity also changing size.
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Many Toronto businesses and institutions dispose of harsh cleaning chemicals, degreasers, and heavy metals through the sewer system. Toronto Water can remove some of these contaminants when the wastewater is treated at one of their treatment plants; however, many toxic chemicals remain and are often released into Lake Ontario. In 2011, over 7 tonnes of cadmium, mercury, lead, and nickel were released into Lake Ontario from Toronto facilities. A study conducted in 2009 and published in 2014 by the University of Toronto and Environment Canada sampled Toronto's tributaries and treated wastewater for PCBs, flame retardants (including polybrominated diphenyl ethers or PBDEs), polycyclic aromatic hydrocarbons (PAHs) and polycyclic musks (PCMs).
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Saegusa-Ito oxidation For acyclic substrates the reaction yields the thermodynamic E-olefin product exclusively. Acyclic substrates This discovery was preceded nearly eight years earlier by a report that treatment of unactivated ketones with palladium acetate yielded the same products in low yields. The major improvement provided by Saegusa and Ito was the recognition that the enol form was the reactive species, developing a method based on silyl enol ethers. Benzoquinone is actually not a necessary component for this reaction; its role is to regenerate palladium(II) from its reduced form palladium(0), so that a smaller amount of expensive palladium(II) acetate is required at the beginning.
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Resins associating to the midblocks (aliphatic olefins, rosin esters, polyterpenes, terpene phenolics) improve adhesion, processing and pressure-sensitive properties. Addition of plasticizers reduces cost, improves pressure-sensitive tack, decrease melt viscosity, decrease hardness, and improve low-temperature flexibility. The A-B-A structure promotes a phase separation of the polymer, binding together the endblocks, with the central elastic parts acting as cross-links; SBCs do not require additional cross-linking, styrene-butadiene-styrene (SBS), used in high-strength PSA applications styrene-ethylene/butylene-styrene (SEBS), used in low self-adhering non-woven applications, styrene-ethylene/propylene (SEP), styrene-isoprene-styrene (SIS), used in low-viscosity high-tack PSA applications, vinyl ethers.
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The description and the generally touted advantages are as follows: #Epoxy: Although aliphatic epoxy materials have been used, the majority of EPD epoxy types are based on aromatic epoxy polymers, most commonly based on polymerization of diglycidal ethers of bis phenol A. The polymer backbone may be modified with other types of chemistries to achieve the desired performance characteristics. Generally, this type of chemistry is used in primer applications where the coating will receive a topcoat, particularly if the coated object needs to withstand sunlight. This chemistry generally does not have good resistance to UV light. However, this chemistry is often used where high corrosion resistance is required.
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Codeine has been used in the past as the starting material and prototype of a large class of mainly mild to moderately strong opioids; such as hydrocodone (1920 in Germany), oxycodone (1916 in Germany), dihydrocodeine (1908 in Germany), and its derivatives such as nicocodeine (1956 in Austria). However, these opioids are no longer synthesized from codeine and are usually synthesized from other opium alkaloids; specifically thebaine. Other series of codeine derivatives include isocodeine and its derivatives, which were developed in Germany starting around 1920. In general, the various classes of morphine derivatives such as ketones, semisynthetics like dihydromorphine, halogeno-morphides, esters, ethers, and others have codeine, dihydrocodeine, and isocodeine analogues.
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The philosophy which discusses the Archeus in the most detail is medieval hermetic science, where we find the occult author Heinrich Cornelius Agrippa speaking at length about a previously purely platonic subject. This he likely derived from his teacher in hermetic science, a man by the name of Trithemius, who studied extensively under certain Neoplatonic philosophers. It is worth mentioning that the Archeus can be broken down into four different ethers: Chemical, Life, Light, and Reflective. To discuss them briefly as certain mystics saw them, the Chemical Ether composes the substances within which energies responsible for the perpetuation of chemical actions in the world exist.
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In addition, control of most named substances is extended to control of all of their ethers, esters, salts and stereoisomers. Due to this complexity in legislation the identification of controlled chemicals in research is often carried out computationally, either by in house systems maintained a company's sample logistics department or by the use commercial software solutions. Automated systems are often required as many research operations can often have chemical collections running into 10Ks of molecules at the 1–5 mg scale, which are likely to include controlled substances, especially within medicinal chemistry research. These may not have been controlled when created, but they have subsequently been declared controlled.
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Unlike the aluminium and gallium trihalides, the boron trihalides are all monomeric. They undergo rapid halide exchange reactions: :BF3 \+ BCl3 → BF2Cl + BCl2F Because of the facility of this exchange process, the mixed halides cannot be obtained in pure form. Boron trifluoride is a versatile Lewis acid that forms adducts with such Lewis bases as fluoride and ethers: :CsF + BF3 → CsBF4 :O(C2H5)2 \+ BF3 → BF3O(C2H5)2 Tetrafluoroborate salts are commonly employed as non- coordinating anions. The adduct with diethyl ether, boron trifluoride diethyl etherate, or just boron trifluoride etherate, (BF3·O(Et)2) is a conveniently handled liquid and consequently is widely encountered as a laboratory source of BF3.
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The tert-butyldiphenylsilyl group was first suggested as a protecting group by Hanessian and Lavalle in 1975. It was designed to supersede the use of Corey's tert-butyldimethylsilyl as a protecting group for alcohols: The novel features that they highlight are the increased resistance to acidic hydrolysis and increased selectivity towards protection of primary hydroxyl groups. The group is unaffected by treatment with 80% acetic acid, which catalyses the deprotection of O-tetrapyranyl, O-trityl and O-tert- butyldimethylsilyl ethers. It is also unaffected by 50% trifluoroacetic acid (TFA), and survives the harsh acidic conditions used to install and remove isopropylidene or benzylidene acetals.
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In 2018, Peavy's paintings were included in the gallery's group exhibition "April 14, 1561." Roberta Smith reviewed the exhibition in The New York Times, and mentioned Peavy's work: “The abstractions representing Ms. Peavy here suggest brightly colored embryos or sleek flying saucers drifting among amniotic fluids or intergalactic ethers.” As interest in previously overlooked female spiritualist artists like Hilma af Klint and Emma Kunz grows, the art world has begun to recognize Paulina Peavy's achievements as an artist. Artist Jane Kaplowitz chose the 2019 exhibition of Paulina Peavy's work at the Andrew Edlin Gallery as her most memorably exhibition of 2019 in Artforum round up of artists' artists.
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Figure 1: Representative Structure of Polyphenyl Ether (PPE) Figure 2: Representative Structure of Polyphenylene Oxide (PPO) Phenyl ether polymers are a class of polymers that contain a phenoxy or a thiophenoxy group as the repeating group in ether linkages. Commercial phenyl ether polymers belong to two chemical classes: polyphenyl ethers (PPEs) and polyphenylene oxides (PPOs). The phenoxy groups in the former class of polymers do not contain any substituents whereas those in the latter class contain 2 to 4 alkyl groups on the phenyl ring. The structure of an oxygen-containing PPE is provided in Figure 1 and that of a 2, 6-xylenol derived PPO is shown in Figure 2.
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Minor mechanical disturbances, such as scraping the inside of a vessel or the dislodging of a deposit, merely twisting the cap may provide sufficient energy for the peroxide to explode or detonate. Peroxide formation is not a significant problem when fresh solvents are used up quickly; they are more of a problem in laboratories which may take years to finish a single bottle. Low- volume users should acquire only small amounts of peroxide-prone solvents, and dispose of old solvents on a regular periodic schedule. To avoid explosive peroxide formation, ethers should be stored in an airtight container, away from light, because both light and air can encourage peroxide formation.
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Sodium 2-hydroxyethyl sulfonate is formed by the reaction of ethylene oxide with sodium hydrogen sulfite in aqueous solution: :Sodium isethionate EO To avoid contamination and suppress the formation of by- products (which are difficult to remove) the reaction must be performed under careful control of mass ratios and process conditions. Excess sulfite (SO32−) or bisulfite (HSO3−) lead to an unpleasant odor of the downstream product, higher levels of ethylene glycol or glycol ethers (formed by the hydrolysis and ethoxylation of ethylene oxide) give hygroscopic and greasy surfactants. Concentrated ethylene glycol-containing sodium 2-hydroxyethyl sulfonate solutions can subsequently mostly be freed from ethylene glycol by continuous extraction with e.g. isopropanol (<0.5%).
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Environmental contaminants stemming from plastic debris, oil spills and dumping of industrial wastes at-sea, in addition to agricultural run-off from terrestrial sources, can lead to bioaccumulation in marine ecosystems and pose a threat to melon-headed whales (as with all marine mammals and long-lived, high trophic level consumers). Persistent organic pollutants (POPs)–include environmental contaminants such as polychlorinated biphenyls (PCBs), organochlorine pesticides e.g. dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) and organobromine compounds such as polybrominated diphenyl ethers (PBDEs)–are lipophilic (fat-soluble) and can accumulate in the blubber of marine mammals. In high concentrations these pollutants can interfere with overall health, hormone levels and impact both the immune and reproductive systems.
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On October 18, 2012 the Advisory Council on the Misuse of Drugs in the United Kingdom released a report about methoxetamine, saying that the "harms of methoxetamine are commensurate with Class B of the Misuse of Drugs Act (1971)", despite the fact that the act does not classify drugs based on harm. The report went on to suggest that all analogues of MXE should also become class B drugs and suggested a catch-all clause covering both existing and unresearched arylcyclohexamines, including 4-MeO-PCP. Sweden's public health agency suggested classifying 4-MeO-PCP as hazardous substance on November 10, 2014. As per Chile's Ley de drogas, aka Ley 20000, all esters and ethers of PCP are illegal.
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Ge(II) dicationic complexes refer to coordination compounds of germanium with a +2 formal oxidation state, and a +2 charge on the overall complex. In some of these coordination complexes, the coordination is strongly ionic, localizing a +2 charge on Ge, while in others the bonding is more covalent, delocalizing the cationic charge away from Ge. Examples of dicationic Ge(II) complexes are much rarer than monocationic Ge(II) complexes, often requiring the use of bulky ligands to shield the germanium center. Dicationic complexes of Ge(II) have been isolated with bulky isocyanide and carbene ligands. Much more weakly coordinated Germanium (II) dications have been isolated as complexes with polyether ligands, such as crown ethers and [2.2.2]cryptand.
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Because many Archaea have adapted to life in extreme environments such as polar regions, hot springs, acidic springs, alkaline springs, salt lakes, and the high pressure of deep ocean water, they possess enzymes that are functional under quite unusual conditions. These enzymes are of potential use in the food, chemical, and pharmaceutical industries, where biotechnological processes frequently involve high temperatures, extremes of pH, high salt concentrations, and / or high pressure. Examples of enzymes identified to date include amylases, pullulanases, cyclodextrin glycosyltransferases, cellulases, xylanases, chitinases, proteases, alcohol dehydrogenase, and esterases. Archaea represent a source of novel chemical compounds also, for example isoprenyl glycerol ethers 1 and 2 from Thermococcus S557 and Methanocaldococcus jannaschii, respectively.
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Chemical structure of PBDEs The family of PBDEs consists of 209 possible substances, which are called congeners (PBDE = C12H(10−x)BrxO (x = 1, 2, ..., 10 = m + n)). The number of isomers for mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, and decabromodiphenyl ethers are 3, 12, 24, 42, 46, 42, 24, 12, 3 and 1, respectively. In the United States, PBDEs are marketed with the trade names DE-60F, DE-61, DE-62, and DE-71 applied to pentaBDE mixtures, DE-79 applied to octaBDE mixtures, and DE 83R and Saytex 102E applied to decaBDE mixtures. The available commercial PBDE products are not single compounds or even single congeners but rather mixtures of congeners.
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Eventually, chemists were able to take these concepts and apply them to synthetic systems. The breakthrough came in the 1960s with the synthesis of the crown ethers by Charles J. Pedersen. Following this work, other researchers such as Donald J. Cram, Jean-Marie Lehn and Fritz Vögtle became active in synthesizing shape- and ion-selective receptors, and throughout the 1980s research in the area gathered a rapid pace with concepts such as mechanically interlocked molecular architectures emerging. The importance of supramolecular chemistry was established by the 1987 Nobel Prize for Chemistry which was awarded to Donald J. Cram, Jean-Marie Lehn, and Charles J. Pedersen in recognition of their work in this area.
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The Cravatt laboratory at The Scripps Research Institute has recently applied this technology to mammalian systems, identifying the N-acyltaurines as previously uncharacterized endogenous substrates for the enzyme fatty acid amide hydrolase (FAAH) and the monoalkylglycerol ethers (MAGEs) as endogenous substrates for the uncharacterized hydrolase KIAA1363. Metabologenomics is a novel approach to integrate metabolomics and genomics data by correlating microbial-exported metabolites with predicted biosynthetic genes. This bioinformatics-based pairing method enables natural product discovery at a larger-scale by refining non-targeted metabolomic analyses to identify small molecules with related biosynthesis and to focus on those that may not have previously well known structures. Fluxomics is a further development of metabolomics.
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Stacki works on several servers at the same time, so it takes about as long to provision any number of servers. The system allows installations via the Preboot Execution Environment (PXE), and supports both an “all servers that boot on this network” and an “all servers in this spreadsheet” method of installations. So if the servers to be installed are on an isolated network, a Stacki tool called insert-ethers can be run to grab each machine that boots on the network and add it to Stacki, commencing an installation if needed. If the servers to be installed are on a shared network, then loading a spreadsheet of machines to install tells Stacki which ones it should install.
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A DSc from the University of Manchester followed in 1911, after which he served a short time at the Imperial College of Science and Technology as Senior Demonstrator in Chemistry. In 1912 Haworth became a lecturer at United College of University of St Andrews in Scotland and became interested in carbohydrate chemistry, which was being investigated at St Andrews by Thomas Purdie (1843–1916) and James Irvine (1877–1952). Haworth began his work on simple sugars in 1915 and developed a new method for the preparation of the methyl ethers of sugars using methyl sulfate and alkali (now called Haworth methylation). He then began studies on the structural features of the disaccharides.
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In the European Union, the directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (see RoHS) bans mercury from certain electrical and electronic products, and limits the amount of mercury in other products to less than 1000 ppm. Article 4 Paragraph 1. e.g. "Member States shall ensure that, from July 1, 2006, new electrical and electronic equipment put on the market does not contain lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE)." There are restrictions for mercury concentration in packaging (the limit is 100 ppm for sum of mercury, lead, hexavalent chromium and cadmium) and batteries (the limit is 5 ppm).
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Ethylene oxide was first reported in 1859 by the French chemist Charles-Adolphe Wurtz, who prepared it by treating 2-chloroethanol with potassium hydroxide: :Cl–CH2CH2–OH + KOH → (CH2CH2)O + KCl + H2O Wurtz measured the boiling point of ethylene oxide as , slightly higher than the present value, and discovered the ability of ethylene oxide to react with acids and salts of metals. Wurtz mistakenly assumed that ethylene oxide has the properties of an organic base. This misconception persisted until 1896 when Georg Bredig found that ethylene oxide is not an electrolyte. That it differed from other ethers — particularly by its propensity to engage in addition reactions, which are typical of unsaturated compounds — had long been a matter of debate.
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He was inspired to conceptualize holistic medicine while a young doctor working for the Grenfell Mission, which served the fisherman families of Newfoundland and Labrador, traveling by dog sled and boat when necessary. "It was out of the ethers, or perhaps from God, that the words 'Treat the whole man, treat the whole man,' kept flashing through my mind, and they have been with me ever since. For the next eighteen years, I gave much thought as to the practical application of a therapy that would include the physical, mental, and spiritual aspects of illness." Because Evarts grew up in a spiritual, humanitarian, and global environment, he was already naturally applying these concepts at the medical mission.
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Silicone grease is widely used as a temporary sealant and a lubricant for interconnecting ground glass joints, as is typically used in laboratory glassware. Although silicones are normally assumed to be chemically inert, several historically significant compounds have resulted from unintended reactions with silicones.Haiduc, I., "Silicone Grease: A Serendipitous Reagent for the Synthesis of Exotic Molecular and Supramolecular Compounds", Organometallics 2004, volume 23, pp. 3–8. . The first salts of crown ethers (OSi(CH3)2)n were produced by reactions of organolithium and organopotassium compounds with silicone greases or the serendipitous reaction of stannanetriol with silicone grease to afford a cage- like compound having three Sn−O−Si−O−Sn linkages in the molecule.
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These highly soluble versions of Lawesson's reagent are created by the reaction of PS with aryl ethers which are different from anisole. For instance butoxybenzene and 2-tert-butylanisole have both been reacted to form more soluble thionation reagents of the 1,3,2,4-dithiadiphosphetane 2,4-disulfide class. The general structure of a 1,3,2,4-dithiadiphosphetane 2,4-disulfide and the reversible generation of the dithiophosphine ylides An important subclass of these compounds are the naphthalen-1,8-diyl 1,3,2,4-dithiadiphosphetane 2,4-disulfides; these are intellectually interesting because the two dithiophosphine ylides are fixed together in space by the rigid naphthalene unit. The reactivity of these compounds is very different from that of 1,3,2,4-dithiadiphosphetane 2,4-disulfides.
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CBS reduction of sulfone in MK-0417 synthesis Asymmetric reduction of a 1,1,1-trichloro-2-keto compound is the first stage of the Corey–Link reaction for synthsis of amino acids and related structures with a choice of either natural or un-natural stereochemistry and various side-chains. Asymmetric reduction of 7-(Benzyloxy)hept-1-en-3-one leads to (S)-7-(Benzyloxy)hept-1-en-3-ol, a chiral alcohol that leads directly to synthesis of kanamienamides, that are currently researched as enamide containing enol ethers that show potent inhibition of cancer cells. The selective formation of the chiral product is achieved by (R)-CBS catalyst with 89% yield and with 91% enantiomeric excess.
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Two chapters of Lü Buwei's (c. 240 BCE) wide-ranging Lüshi chunqiu "The Annals of Lu Buwei" repeat the ying 應 "acoustic resonance" zither-string analogy, and explain how phenomena that are of the same lei 類 "kind; category" mutually zhao 召 "resonate; attract" one another. > Things belonging to the same category naturally attract each other [類同相召]; > things that share the same ethers [qi 氣] naturally join together; and notes > that are comparable naturally resonate [應] to one another. Strike the note > gong [宮] on one instrument and other strings tuned to the gong note will > vibrate [應]; strike the note jue [角] and other strings tuned to the jue note > will vibrate [應].
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Crystal structure of a nitrobenzene bound within a hemicarcerand reported by Cram and coworkers Cram expanded upon Charles Pedersen's ground-breaking synthesis of crown ethers, two-dimensional organic compounds that are able to recognize and selectively combine with the ions of certain metal elements. He synthesized molecules that took this chemistry into three dimensions, creating an array of differently shaped molecules that could interact selectively with other chemicals because of their complementary three-dimensional structures. Cram's work represented a large step toward the synthesis of functional laboratory-made mimics of enzymes and other natural molecules whose special chemical behavior is due to their characteristic structure. He also did work in stereochemistry and Cram's rule of asymmetric induction is named after him.
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Important epoxy resins are produced from combining epichlorohydrin and bisphenol A to give bisphenol A diglycidyl ethers. Structure of bisphenol-A diglycidyl ether epoxy resin: n denotes the number of polymerized subunits and is typically in the range from 0 to 25 Increasing the ratio of bisphenol A to epichlorohydrin during manufacture produces higher molecular weight linear polyethers with glycidyl end groups, which are semi-solid to hard crystalline materials at room temperature depending on the molecular weight achieved. This route of synthesis is known as the "taffy" process. More modern manufacturing methods of higher molecular weight epoxy resins is to start with liquid epoxy resin (LER) and add a calculated amount of bisphenol A and then a catalyst is added and the reaction heated to circa .
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The use of photoredox catalysis to generate reactive heteroatom-centered radicals was first explored in the 1990s. [Ru(bipy)3]2+ was found to catalyze the fragmentation of tosylphenylselenide to phenylselenolate anion and tosyl radical and that a radical chain propagation mechanism allowed the addition of tosyl radical and phenylseleno- radical across the double bond of electron rich alkyl vinyl ethers. Since phenylselenolate anion is readily oxidized to diphenyldiselenide, the low quantities of diphenyldiselenide observed was taken as an indication that photoredox-catalyzed fragmentation of tosylphenylselenide was only important as an initiation step, and that most of the reactivity was due to a radical chain process. Addition of Tosylphenylselenide across an olefin Heteroaromatic additions to olefins include multicomponent oxy- and aminotrifluoromethylation reactions.
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Chemical structure of colneleic acid Divinylether fatty acids contain a fatty acid chemically combined with a doubly unsaturated carbon chain linked by an oxygen atom (ether). Fatty acid hydroperoxides generated by plant lipoxygenases from linoleic and linolenic acids are known to serve as substrates for a divinyl ether synthase which produces divinyl ether fatty acids. Up to date divinyl ethers were detected only within the plant kingdom. The discovery of that class of compounds dates back to 1972, when the structures of two ether C18 fatty acids generated by homogenates of the potato tuber were described. These compounds, named colneleic acid (from linoleic acid) and colnelenicacid (from linolenic acid), could be also produced in potato leaves and tomato roots by rearrangement of 9-hydroperoxides.
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In 2009, Susan Reutman, an epidemiologist with the U.S. National Institute for Occupational Safety and Health's Division of Applied Research and Technology, announced a federal effort to evaluate the effectiveness of downdraft vented nail tables (VNTs) in removing potential nail polish chemical and dust exposures from the technician's work area. These ventilation systems have potential to reduce worker exposure to chemicals by at least 50%. Many nail technicians will often wear masks to cover their mouth and nose from inhaling any of the harsh dust or chemicals from the nail products. According to Reutman, a growing body of scientific literature suggests that some inhaled and absorbed organic solvents found in nail salons such as glycol ethers and carbon disulfide may have adverse effects on reproductive health.
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Kocienski has made contributions to the design and development of new organometallic reagents in synthesis, and the applications of synthetic methods to complex natural products. Early work with Basil Lythgoe on the scope and stereochemistry of the Julia olefination with alpha-metallated sulphone reagents emphasised the value of this method in organic chemistry. His major contribution has been to research the synthesis and chemistry of novel metallated (lithium, copper and nickel) enol ethers, and to develop the uses of these intermediates in the synthesis of oxacyclic and geometrically defined alkene units in natural products of biological significance. Kocienski has synthesised the insecticide milbemycin beta 3, the potassium channel blocker talaromycin B, the hypotensive agent lacrimin, and the antihypertensive agent zoapatanol.
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Adduct purification is a technique for preparing extremely pure simple organometallic compounds, which are generally unstable and hard to handle, by purifying a stable adduct with a Lewis acid and then obtaining the desired product from the pure adduct by thermal decomposition. Epichem Limited is the licensee of the major patents in this field, and uses the trademark EpiPure to refer to adduct-purified materials; Professor Anthony Jones at Liverpool University is the initiator of the field and author of many of the important papers. The choice of Lewis acid and of reaction medium is important; the desired organometallics are almost always air- and water-sensitive. Initial work was done in ether, but this led to oxygen impurities, and so more recent work involves tertiary amines or nitrogen-substituted crown ethers.
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This is followed by SN2 attack of the arylmethyloxonium ion at the methyl group by either pyridine or chloride ion (depending on the substrate) to give the free phenol and, ultimately, N-methylpyridinium chloride, either directly or by subsequent methyl transfer from methyl chloride to pyridine.400x400px Another classical (but again, harsh) method for the removal of the methyl group of an aryl methyl ether is to heat the ether to reflux in a solution of hydrogen bromide or hydrogen iodide in acetic acid (b.p. 118 °C) or concentrated hydrobromic or hydroiodic acid. The cleavage of ethers by hydrobromic or hydroiodic acid proceeds by a very similar mechanism, in which the highly acidic HBr or HI serves to protonate the ether, followed by displacement by bromide or iodide, both of which are excellent nucleophiles.
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Cannel coal of the Pennsylvanian subperiod from NE Ohio used to produce coal oil Coal oil is a shale oil obtained from the destructive distillation of cannel coal, mineral wax, or bituminous shale, once used widely for illumination. Chemically similar to the more refined, petroleum-derived kerosene, it consists mainly of several hydrocarbons of the alkane series, with 10 to 16 carbon atoms in each molecule, with a boiling point of 175°C to 325°C (347°F to 617°F), higher than gasoline or the petroleum ethers, and lower than the oils. Because kerosene was first derived from cannel coal, classified as terrestrial type of oil shale,Dyni (2006), pp. 3–4 it continued to be popularly referred to as "coal oil" even after production shifted to petroleum as a feedstock.
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2,2,5,5-tetramethyltetrahydrofuran (TMTHF) or 2,2,5,5-tetramethyloxolane (TMO) is a heterocyclic compound with the formula , or (CH3)2(C(CH2)2OC)(CH3)2. It can be seen as derivative of tetrahydrofuran (oxolane) with four methyl groups replacing four hydrogen atoms on each of the carbon atoms in the ring that are adjacent to the oxygen. The absence of hydrogen atoms adjacent to the oxygen means that TMTHF (TMO) does not form peroxides, unlike other common ethers such as tetrahydrofuran, diethyl ether and CPME. The compound has been demonstrated as a non-polar solvent in research chemistry, having similar properties to tolueneFergal Byrne, Bart Forier, Greet Bossaert, Charly Hoebers, Thomas J Farmer, James H Clark, Andrew J Hunt (2017) 2, 2, 5, 5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents.
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These products include detergents, thickeners, solvents, plastics, and various organic chemicals such as ethylene glycol, ethanolamines, simple and complex glycols, polyglycol ethers, and other compounds. Although it is a vital raw material with diverse applications, including the manufacture of products like polysorbate 20 and polyethylene glycol (PEG) that are often more effective and less toxic than alternative materials, ethylene oxide itself is a very hazardous substance. At room temperature it is a flammable, carcinogenic, mutagenic, irritating, and anaesthetic gas. As a toxic gas that leaves residue on items it contacts including food and spices, ethylene oxide is a surface disinfectant that is widely used in hospitals and the medical equipment industry to replace steam in the sterilization of heat-sensitive tools and equipment, such as disposable plastic syringes.
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SPMDs, or semipermeable membrane devices, are a passive sampling device used to monitor trace levels of organic compounds with a log Kow > 3. SPMDs are an effective way of monitoring the concentrations of chemicals from anthropogenic runoff and pollution in the marine environment because of their ability to detect minuscule levels of chemical. The data collected from a passive sampler is important for examining the amount of chemical in the environment and can therefore be used to formulate other scientific research about the effects of those chemicals on the organisms as well as the environment. Examples of commonly measured chemicals using SPMDs include: PAHs (Polycyclic aromatic hydrocarbons), PCBs (polychlorinated biphenyls), PBDEs (polybrominated diphenyl ethers), dioxins and furans as well as hydrophobic waste-water effluents like fragrances, triclosan and phthalates.
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Forest fire retardants that are used are generally considered non- toxic, but even less-toxic compounds carry some risk when organisms are exposed to large amounts. Fire retardants used in firefighting can be toxic to fish and wildlife as well as firefighters by releasing dioxins and furans when halogenated fire retardants are burned during fires, and drops within 300 feet of bodies of water are generally prohibited unless lives or property are directly threatened. The US Forest Service is the governing agency that conducts research and monitors the effect of fire retardants on wildland systems in the US. A study published in June 2014 found that marine bacteria have the ability to manufacture a non-synthetic source of chemically identical polybrominated diphenyl ethers (PBDEs). These chemicals are used as flame retardant, but are known to be toxic to the environment.
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In 1997, Sinaÿ and co-workers reported an alternative route to the synthesis (shown below) that did not involve cleavage of the bond at the anomeric position (the glycosidic bond). In this case, the major product formed had maintained its original configuration at the anomeric position. 600px (Bn = benzyl, i-Bu = isobutyl) Sinaÿ proposed this reaction went through the following transition state: 250px Sinaÿ also discovered that titanium (IV) derivatives such as [TiCl3(OiPr)] worked in the same reaction as a milder version of the Lewis acid, i-Bu3Al, which goes through a similar transition state involving the retention of configuration at the anomeric center. In 1988, Adam reported a modification of the reaction that used catalytic amounts of palladium (II) salts, which brought about the same conversion of enol ethers into carbosugars in a more environmentally friendly manner.
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The need to clarify the definition of 'polyphenols' in the light of the extensive research into this large substance class and of increasingly ambiguous use of the polyphenol term led Stéphane Quideau, University of Bordeaux 1, France, to offer a definition not given formal status by IUPAC: :The term "polyphenol" should be used to define compounds exclusively derived from the shikimate/phenylpropanoid and/or the polyketide pathway, featuring more than one phenolic unit and deprived of nitrogen-based functions. Structurally, this definition continues to steer the definition away from exclusively man-made structures without corresponding natural products, and explicitly excludes monophenolic structures (man-made or naturally occurring) and their derivatives, e.g., phenyl esters, methyl phenyl ethers and O-phenyl glycosides. This definition departs from the WBSSH definition in terms of physicochemical behavior, with its lack of reference to solubility, precipitation, and complexation phenomena.
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In New Zealand and Australia, GHB, 1,4-B, and GBL are all Class B illegal drugs, along with any possible esters, ethers, and aldehydes. GABA itself is also listed as an illegal drug in these jurisdictions, which seems unusual given its failure to cross the blood–brain barrier, but there was a perception among legislators that all known analogues should be covered as far as this was possible. Attempts to circumvent the illegal status of GHB have led to the sale of derivatives such as 4-methyl-GHB (γ-hydroxyvaleric acid, GHV) and its prodrug form γ-valerolactone (GVL), but these are also covered under the law by virtue of their being "substantially similar" to GHB or GBL and; so importation, sale, possession and use of these compounds is also considered to be illegal. In Chile, GHB is a controlled drug under the law (psychotropic substances and narcotics).
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Safe Planet Campaign logo Safe Planet: the United Nations Campaign for Responsibility on Hazardous Chemicals and Wastes is the UN Environment Programme (UNEP) and UN Food and Agricultural Organization-led global public awareness and outreach campaign for ensuring the safety of human health and the environment against hazardous chemicals and wastes. The Secretariats of the Basel Convention, the Rotterdam Convention and the Stockholm Convention on Persistent Organic Pollutants, the three leading global chemicals and waste management instruments, provide the measures, new initiatives and solutions to deal with the growing problems of hazardous chemicals and wastes. Basel, Rotterdam and Stockholm Conventions encompass the management of hazardous chemicals, especially the persistent organic pollutants (POPs), which are covered by all three treaties. The Conventions target chemical pollutants like dioxins and furans, hazardous pesticides and DDT, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), PFOS, and the heavy metals: arsenic, cadmium, mercury and lead.
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The name of the group is derived from the Aether, the first-born Greek elemental god of air (and at that time a general term for any highly volatile compound) and "hyle", referring to "stuff". The name "ethyl" was coined in 1835 by the Swedish chemist Jöns Jacob Berzelius.In 1834, the German chemist Justus Liebig had argued that the group C2H5 constituted a "radical" (a cluster of atoms that did not undergo changes during chemical reactions). (See: Justus Liebig (1834) "Ueber die Constitution des Aethers und seiner Verbindungen" (On the composition of ethers and their compounds), Annalen der Pharmacie, 9 : 1–39.) In reporting on Liebig's findings (and related work by others), Berzelius coined the names "methyl" and "ethyl" for the "radicals" CH3 and C2H5, respectively. From Jacob Berzelius, Årsberättelsen om framsteg i fysik och kemi [Annual report on progress in physics and chemistry] (Stockholm, Sweden: P.A. Norstedt & Söner, 1835), p.
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The band was formed in 1996 by R.E.M.'s Peter Buck (guitar), Barrett Martin of the Screaming Trees (drums and percussion), Justin Harwood of Luna and The Chills (bass guitar, double bass), and Skerik of Critters Buggin (saxophones). The band was named, at Harwood's suggestion, after a reptile from his native New Zealand. Originally a project to get musician friends some soundtrack work, the project evolved into an active band, doing occasional live shows, and recording their first album Breaking the Ethers, encompassing a sound influenced by various styles of music, from Lebanese and Asian music to more traditional Western folk music. The band expanded in 1998, adding guitarist Scott McCaughey on guitar, Steve Berlin on saxophone and flute, Craig Flory on clarinets and saxophones, Elizabeth Pupo- Walker on congas and other percussion, and Mike Stone on drum kit; with Stone now on drums, Barrett Martin focused more on vibes and marimba.
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Synthesis of bisphenol A diglycidyl ether The most common epoxy resins are based on reacting epichlorohydrin (ECH) with bisphenol A, resulting in a different chemical substance known as bisphenol A diglycidyl ether (commonly known as BADGE or DGEBA). Bisphenol A-based resins are the most widely commercialised resins but also other bisphenols are analogously reacted with epichlorohydrin, for example Bisphenol F. In this two-stage reaction, epichlorohydrin is first added to bisphenol A (bis(3-chloro-2-hydroxy-propoxy)bisphenol A is formed), then a bisepoxide is formed in a condensation reaction with a stoichiometric amount of sodium hydroxide. The chlorine atom is released as sodium chloride (NaCl), the hydrogen atom as of water. Higher molecular weight diglycidyl ethers (n ≥ 1) are formed by the reaction of the bisphenol A diglycidyl ether formed with further bisphenol A, this is called prepolymerization: Synthesis of bisphenol- A-diglycidyl ether with a high molar mass A product comprising a few repeat units (n = 1 to 2) is a viscous, clear liquid; this is called a liquid epoxy resin.
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1,4-butanesultone reacts smoothly with nucleophiles such as ammonia to form the corresponding zwitterionic, usually very water-soluble sulfobutylbetaines. Synthese von 4-Aminobutan-1-sulfonsäure aus 1,4-Butansulton Sulfobetaines with longer alkyl chains (CnH2n+1 mit n > 10) show interesting properties as surface-active compounds (surfactants, detergents) with antimicrobial properties. Synthese eines Alkylpiperidinsulfobetains-Surfactants In the reaction of N-N- butylimidazole with 1,4-Butansultone in Toluene in a 98% yield is formed 1-butylimidazolium-3-(n-butylsulfonate) Synthese von ionischen Flüssigkeiten vom Chlorbutylsulfonat-Typ 1-Butylimidazolium-3-(n-butylsulfonate) catalyses as a component of multifunctional catalysts the reaction of platform chemicals from biomass (for example levulinic acid or itaconic acid) into the corresponding lactones, diols or cyclic ethers. Aminoalkylphosphonic acids (such as aminomethane diphosphonic acid, accessible from phosphorus trichloride, formamide and phosphonic acid) form with 1,4-butanesultone N-(sulfobutyl)aminomethane diphosphonic acids: Synthese von N-(Sulfobutyl)aminomethandiphosphonsäure-Komplexbildnern N-(sulfobutyl)aminomethane diphosphonic acid is characterized by very high water solubility (< 1000 g·l−1) and a strong capability as complexing agent and water softener.
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A further misconception is that the Misuse of Drugs Act simply lists a few hundred substances (e.g. MDMA, Fentanyl, Amphetamine, etc.) and compliance can be achieved via checking a CAS number, chemical name or similar identifier. However, the reality is that in most cases all ethers, esters, salts and stereo isomers are also controlled and it is impossible to simply list all of these. The act contains several "generic statements" or "chemical space" laws, which aim to control all chemicals similar to the "named" substance, these provide detailed descriptions similar to Markushes, a good example of a few of these are found in the Misuse of Drugs Act 1971 (amendment) order 2013. Due to this complexity in legislation the identification of controlled chemicals in research is often carried out computationally, either by in house systems maintained a company’s sample logistics department or by the use commercial software solutions. Automated systems are often required as many research operations can often have chemical collections running into 10Ks of molecules at the 1–5 mg scale, which are likely to include controlled substances, especially within medicinal chemistry research.
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On February 14, three days after the first round of qualifying, David Hyder, the crew chief for Michael Waltrip and Bobby Kennedy, competition director for Michael Waltrip Racing (MWR) (cars #44 and #55) and Waltrip-PPI Racing (#00) were ejected from the track by NASCAR officials. Earlier, the intake manifold from Waltrip's #55 car had been confiscated by NASCAR when "an unknown substance" was found in it during post-qualifying inspection. When a new manifold was installed and the engine test-run, the same substance was found in the new manifold, resulting in NASCAR impounding the entire car and disallowing Waltrip's qualifying time, which was 25th-fastest. Just before 6 PM US EST, NASCAR held a press conference at which it was announced that both Hyder and Kennedy were suspended indefinitely, Hyder fined $100,000, Waltrip docked 100 championship points, and the team, owned by Waltrip's wife, Buffy, were docked 100 car owner points for violations that included a violation of the rule (in place through the 2010 season) prohibiting the blending of gasoline with "alcohols, ethers, or other oxygenates"; this quickly became known among the media and fans as "rocket fuel".
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