The containers each held around 500,000 pounds of organic peroxides.
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Some organic peroxides also produce flammable vapors as they decompose.
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Last week, a chemical plant containing stockpiles of dangerous organic peroxides exploded.
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Organic peroxides stored there need to be refrigerated or they become unstable.
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Some of our organic peroxides products burn if not stored at low temperature.
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He also said that Arkema had numerous safety protocols for handling organic peroxides.
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As temperatures increased in the trailers that housed flammable organic peroxides, three spontaneously ignited.
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It employs about 210 workers to manufacture organic peroxides, used in the manufacture of plastics.
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The Arkema plant manufactures organic peroxides, which are used in making plastic and other materials.
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The plant has also faced state penalties, including two for improper storage of organic peroxides.
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But industrial-grade peroxides like those stored in the Arkema plant can combust if not properly cooled.
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The plant housed extremely flammable organic peroxides that required refrigeration, as once they heat up, they ignite.
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The evacuation ended after officials set fire to the storage trailers to burn up all of the peroxides.
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Explosions were reported at the plant early Thursday morning, after trailers containing organic peroxides caught fire, the company said.
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The chemicals produced at the Arkema plant, called organic peroxides, present high risks because of their vulnerability to heat.
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Its Crosby plant produces liquid organic peroxides found in countertops and acrylic-based paints and coatings in auto parts.
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Organic peroxides are acids that can be used to synthesize other chemicals commonly found in disinfectants or cleaning products.
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" He said organic peroxides of different grades were released, creating "a pop in the containers where they were being stored.
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The peroxides were moved to refrigerated trailers, which were then moved to higher ground, but three could not be relocated.
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That came after a container of organic peroxides exploded and caught fire early Thursday, sending acrid smoke into the air.
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At least two containers containing organic peroxides burned down, with another six likely to follow in the coming days, Click2Houston reported.
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" Brett Fors, a chemistry professor at Cornell, explains that when peroxides combust, "basically they decompose to nontoxic byproducts — C02 and water.
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One of nine containers with the organic peroxides had caught fire, and Rennard said Arkema expected the remaining eight to burn eventually.
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The plant manufactures organic peroxides, chemical compounds used in manufacturing construction materials, which can ignite when not stored at a low temperature.
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The danger comes from the facility's store of organic peroxides, which need to be kept cool or else they become highly reactive.
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" What he said happened: Organic peroxides of different grades were released, creating "a pop in the containers where they were being stored.
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Peroxides are chemicals that bind one oxygen molecule to another, Michael King, chair of chemistry at George Washington University explains in an email.
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The company reported more than 59,000 lbs of emissions from the burning of organic peroxides that caught fire because they were not refrigerated.
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"We are assuming exposure to smoke from a fire containing organic peroxides and/or degradation products of hydrocarbons and alcohols," the company wrote.
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It has over 13,000 five-star reviews, and it whitens teeth naturally without the harsher peroxides that can be irritating for sensitive teeth.
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Vice wrote the chemicals in question are the facility's stockpile of organic peroxides, highly volatile substances used in the production of rubber and plastics.
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The investigation will also look at whether unstable chemical, like organic peroxides, should have been addressed in Arkema's risk management plans, Mr. Banks said.
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Arkema said further explosions of organic peroxides stored on site were possible and urged people to stay away as the fire burns itself out.
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The chemical plant is run by Arkema Group and contains organic peroxides, which need to be kept cool or else they become highly flammable.
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In a tweet Wednesday, the coast guard warned the public not to touch the containers, because three were carrying organic peroxides, which can cause irritation.
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And in 1999, the plant suffered an explosion that sent a ground-shaking boom across Crosby, an episode that was also attributed to organic peroxides.
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Federal Emergency Management Agency administrator Brock Long is calling the plume "incredibly dangerous," noting that the organic peroxides at the facility pose threats to human health.
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Thursday's explosions was set in motion after Hurricane Harvey's floodwaters knocked out power and backup generators, disabling the refrigeration needed to keep the organic peroxides stable.
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The Arkema plant in Crosby that produces organic peroxides has been closed since Friday but has had a skeleton staff of about a dozen in place.
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Harvey dropped five feet of water on the Crosby plant, cutting off power to low-temperature warehouses meant to keep cool organic peroxides used in plastics production.
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As a result, containers of organic peroxides — a family of chemicals manufactured by the company — warmed up and began to burn in the early morning on Aug.
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"Organic peroxides are extremely flammable and, as agreed with public officials, the best course of action is to let the fire burn itself out," the company announced.
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Flooding from Hurricane Harvey knocked out electricity at the plant and also disabled backup systems meant to keep a class of unstable chemicals, called organic peroxides, cool.
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"Organic peroxides are extremely flammable and, as agreed with public officials, the best course of action is to let the fire burn itself out," the company said.
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Arkema's Crosby site makes organic peroxides, highly reactive chemicals commonly used in the rubber and plastics industry that were also employed in terror attacks in Paris and Brussels.
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Seven police, fire and emergency medical technicians sued Arkema in Harris County District Court alleging that negligence led flammable organic peroxides to ignite after the plant lost power.
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Two small containers of highly volatile organic peroxides have already exploded, and residents living within a 1.5-mile radius of the Houston-area plant were asked to evacuate.
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"Organic peroxides are extremely flammable and, as agreed with public officials, the best course of action is to let the fire burn itself out," the company said Thursday.
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The plant manufactured "organic peroxides," chemicals used to make plastics, and some of these reactive materials had to be stored below 20 degrees Fahrenheit to keep from catching fire.
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The company makes liquid organic peroxides used primarily in the production of common consumer products, ranging from headlights assemblies for the automotive industry, to PVC for pipes, packaging and siding.
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"The reckless assault was the misrepresentation by a highly placed corporate official" of the dangers of organic peroxides that burned after the plant flooded, said Harris County District Attorney Kim Ogg.
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The Crosby plant produces liquid organic peroxides used primarily in the production of common consumer products ranging from headlights assemblies for the automotive industry, to PVC for pipes, packaging and siding.
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When the steadily rising waters from Harvey blew out the energy lines supplying power to the Arkema chemical plant's cooling system, highly volatile organic peroxides at the plant started to warm.
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All nine trailers at the Harvey-wrecked chemical site, which were filled with highly flammable organic peroxides that require refrigeration, have now burned, the Harris County Fire Marshal's office said Sunday night.
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The plant — one of global chemical giant Arkema's facilities that stores organic peroxides used to make plastics, rubbers, and explosives — flooded as Hurricane Harvey dumped trillions of gallons of rain across Texas.
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Tourists and locals banded together to help authorities clean up the mess, but police told people to be careful, because some of the containers contained organic peroxides which can be an irritant.
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The containers, which each held around 500,000 pounds of organic peroxides, burned for days, leading to a controlled burn of the remaining chemical containers that had not then ignited on their own.
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Organic peroxides were one of the materials used to craft bombs for ISIS attacks in Paris and Brussels, and need to be kept at a safe temperature or will catch fire and detonate.
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Arkema added that because the chemicals — organic peroxides used in kitchen countertops, polystyrene cups and plates, and other products — were stored at multiple locations at the facility, there was the chance of further explosions.
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But when floodwaters cut power to the trailers, the peroxides decomposed, heated up and caught fire, forcing the evacuation of 200 people living within a 1-1/2-mile (2.4-km)radius of the plant.
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At the Friday news conference, Daryl Roberts, vice president of manufacturing for Arkema's American division,said that about 500,000 pounds of organic peroxides, which are used in making plastics and other materials, were in the trailers.
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An earlier version of this article misidentified the Arkema executive who said at a Friday morning news conference that about 500,000 pounds of organic peroxides were in the trailers at a chemical plant in Crosby, Tex.
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Rachel Moreno, a spokeswoman for the Harris County Fire Marshal's Office, said fire officials know that one trailer filled with organic peroxides and possibly a second trailer was on fire at the Arkema plant in Crosby.
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During Harvey the crew working during the storm moved the peroxides to refrigerated trailers as a last resort to keep them from decomposing and catching fire at the plant located 27 miles (43 km) east of Houston.
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Arkema, a French company, said all four of its systems to cool the organic peroxides produced at its Crosby, Texas, plant and stored onsite in refrigerated containers were expected to fail, triggering their degradation and eventually more fires.
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Local firefighters under the watch of the U.S. Environmental Protection Agency and the Texas Commission on Environmental Quality performed a controlled burn of the organic peroxides on Sunday in order to eliminate any vestiges and reduce the danger.
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The company evacuated remaining workers on Tuesday, and Harris County ordered the evacuation of residents in a 1.5-mile(2.4-km) radius of the plant that makes organic peroxides used in the production of plastic resins, polystyrene, paints and other products.
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Some organic peroxides products burn if not stored at low temperature * Arkema says not to return to area within evacuation zone until local emergency response authorities announce it is safe to do so Source text for Eikon: Further company coverage:
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For years, chemical safety experts, including the Chemical Safety Board, have urged the E.P.A. to regulate chemicals that may not be highly toxic, but may cause violent explosions or fires — like the organic peroxides that caused the explosions in Crosby.
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There were also no signs of the drama that unfolded at the plant the weekend before, when a crew of 11 workers scrambled to move a half million pounds of liquid organic peroxides from an overheating warehouse to refrigerated truck trailers.
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The company explained that despite following their hurricane preparation plan and setting up an evacuation zone in an area 1.5 miles from the plant, extreme flooding affected the facility which makes organic peroxides used in the production of plastic resins, paints and other products.
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Seven police, fire and emergency medical technicians sued Arkema in Harris County District Court for at least $1 million, alleging negligence by the company and executives led flammable organic peroxides stored at the site to ignite after the plant lost power during the storm.
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Flooding from Harvey knocked out electricity to the plant as well as backup systems meant to keep the chemicals, called organic peroxides, cool and stable, forcing an 215-person "ride-out" crew to move them around in trailers as the waters rose before abandoning the plant under the local authorities' orders.
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Peroxides play important roles in biology. Hundreds of peroxides and hydroperoxides are known, being derived from fatty acids, steroids, and terpenes. Derived from fatty acids are a number of 1,2-dioxenes. The biosynthesis prostaglandins proceeds via an endoperoxide, a class of bicyclic peroxides.
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Cumene forms peroxides upon long exposure to air.CDC - NIOSH Pocket Guide to Chemical Hazards Tests for peroxides are routinely conducted before heating or distilling.
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During storage, potassium forms peroxides and superoxides. These peroxides may react violently with organic compounds such as oils. Both peroxides and superoxides may react explosively with metallic potassium. Because potassium reacts with water vapor in the air, it is usually stored under anhydrous mineral oil or kerosene.
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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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Note the blackening (left) of initially yellowish (right) starch. Several analytical methods are used for qualitative and quantitative determination of peroxides. A simple qualitative detection of peroxides is carried out with the iodine-starch reaction. Here peroxides, hydroperoxides or peracids oxidize the added potassium iodide into iodine, which reacts with starch producing a deep-blue color.
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The peroxides are much less reactive than the peroxyacids. The use of hydrogen peroxide even requires a catalyst. In addition, using organic peroxides and hydrogen peroxide tends to generate more side-reactivity due to their promiscuity.
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Decahydronaphthalene easily forms explosive organic peroxides upon storage in the presence of air.
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The 2017 Arkema plant explosion was an industrial disaster that took place during Hurricane Harvey in Crosby, Texas. Flooding from the hurricane disabled the refrigeration system at the plant which manufactured organic peroxides. The unrefrigerated organic peroxides decomposed and self-ignited.
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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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They are also used for the oxidation of amines and thioethers to amine oxides and sulfoxides. The laboratory applications of the valued reagent mCPBA illustrate these reactions. Reaction of peroxycarboxylic acids with acid chlorides affords diacyl peroxides: :RC(O)Cl + RC(O)O2H → (RC(O))2O2 \+ HCl The oxidizing tendency of peroxides is related to the electronegativity of the substituents. Electrophilic peroxides are stronger oxygen-atom transfer agents.
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Because of the formation of peroxides, it should be protected from heat, light and air.
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Thus, organic peroxides are useful as initiators for some types of polymerisation, such as the epoxy resins used in glass-reinforced plastics. MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds, and this process has been used in explosives. Organic peroxides, like their inorganic counterparts, are powerful bleaching agents.
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Commercial formulations occasionally consist of mixtures of organic peroxides, which may or may not be phlegmatized.
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It may form unstable peroxides and it can soften many plastics, attack plastics, rubber and coatings.
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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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Commercial diethyl ether is typically supplied with trace amounts of the antioxidant butylated hydroxytoluene (BHT), which reduces the formation of peroxides. Storage over sodium hydroxide precipitates the intermediate ether hydroperoxides. Water and peroxides can be removed by either distillation from sodium and benzophenone, or by passing through a column of activated alumina.
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One danger posed by THF follows from its tendency to form the highly explosive peroxides tetrahydrofuran hydroperoxide on storage in air. :300px To minimize this problem, commercial samples of THF are often inhibited with butylated hydroxytoluene (BHT). Distillation of THF to dryness is avoided because the explosive peroxides concentrate in the residue.
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Inactivation of GPX4 leads to an accumulation of lipid peroxides, resulting in ferroptotic cell death. Mutations in GPX4 cause spondylometaphyseal dysplasia.
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The hallmark feature of ferroptosis is the iron- dependent accumulation of oxidatively damaged phospholipids (i.e. lipid peroxides). This occurs when free radical molecules take electrons from a lipid molecule, promoting their oxidation by oxygen. The primary cellular mechanism of protection against ferroptosis is mediated by GPX4, a glutathione-dependent peroxidase that converts lipid peroxides into non-toxic lipid alcohols.
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Alkenyl peroxides can be formed by acid catalyzed condensation of ketones with organic hydroperoxides or hydrogen peroxide. This has been suggested based on the characterization of the corresponding products of decomposition. Alkenyl peroxides could also occur as unwanted byproducts in the Baeyer–Villiger oxidation when using hydrogen peroxide, which would diminish the effectiveness of this reaction.
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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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Liquid cleansers that dentures can be immersed in include: bleaches e.g. sodium hypochlorite; effervescent solutions e.g. alkaline peroxides, perborates and persulphates; acid cleaners.
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A common practice in chemical labs is to use steam (thus limiting the temperature to ) when ether must be heated or distilled. The diffusion of diethyl ether in air is (298 K, 101.325 kPa). Ether is sensitive to light and air, tending to form explosive peroxides. Ether peroxides have a higher boiling point than ether and are contact explosives when dry.
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Some mixtures containing peroxides and polymerizable monomers may also exhibit SADTs. For example, mixtures of vinyltrimethoxysilane, peroxides and stabilizers are used commercially for cross-linking polyethylene to make PEX pipe. These mixtures are typically liquid solutions that are shipped to where they are used to graft alkoxysilane groups to polyethylene. In such mixtures decomposition of the peroxide can initiate exothermic radical polymerization of the vinyltrimethoxysilane.
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In mammals there are pathways for the metabolism of peroxides. These pathways make use of different enzymes, but of the same sort, peroxidases. The phase 1 metabolism of peroxides is an overall peroxidase-catalyzed reaction. For bis(trifluoromethyl)peroxide this will be the following reaction: Peroxidase + C₂F₆O₂ → 2CF₃O⁻ The peroxidase will then undergo two sequential electron transfers to come back into its beginning form.
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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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Infrared spectroscopy shows formation of carbonyl groups, epoxides, and peroxides. Coating with polyethylene or wax can slow the oxidation temporarily, while coating with glass increases stability indefinitely.
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Additionally, refrigerated trailers were used by Arkema as a final emergency backup and when warehouse refrigeration systems need to be shut down for maintenance work. When filled with a full tank of fuel, the trailers could keep the organic peroxides at a safe temperature for more than one week. Arkema stored and transported the organic peroxides in plastic or containers. These were typically stacked on pallets and shrink-wrapped together.
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A sample of sodium peroxide. The alkali metals react with oxygen to form several different compounds: suboxides, oxides, peroxides, superoxides, and ozonides. They all react violently with water.
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In addition, the glutathione S-transferases show high activity with lipid peroxides. These enzymes are at particularly high levels in the liver and also serve in detoxification metabolism.
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The manufacture and degradation of o-dianisidine, like other benzidene derivatives, has attracted regulatory attention. It is also used as a reagent in biochemistry in testing for peroxides.
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Like most peroxides, is a powerful bleaching agent. It has been used for the bleaching of flour, fats, oils, waxes, and cheeses, as well as a stain remover.
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Glutathione (GSH) is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by reactive oxygen species such as free radicals, peroxides, lipid peroxides, and heavy metals. It is a tripeptide with a gamma peptide linkage between the carboxyl group of the glutamate side chain and cysteine. The carboxyl group of the cysteine residue is attached by normal peptide linkage to glycine.
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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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The tetraethylammonium salt is also known. Representative reactions of these salts involve using superoxide as a nucleophile, e.g., in converting alkyl bromides to alcohols and acyl chlorides to diacyl peroxides.
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Benzoyl peroxide is one of the most important organic peroxides in terms of applications and the scale of its production. It is often used as a convenient oxidant in organic chemistry.
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Elsewhere in the literature, other examples of anti-Markovnikov additions were observed by Whitmore and Homeyer as well as Sherril, Mayer and Walter, all of whom rejected Kharasch's conclusions. They instead argued that the direction in which the reaction proceeds is determined not by the presence or absence of peroxides, but by the nature of the solvent in which the reaction is taking place. In this paper, Kharasch analyzed one at a time the effects of temperature, solvent, and light on the direction in which the reaction proceeded. He concluded that the presence of peroxides was the driving force for anti-Markovnikov addition and that any changes in temperature, solvent, or light affected the orientation of addition only through the chemistry of the peroxides.
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Ketone peroxides, including acetone peroxide and methyl ethyl ketone peroxide, find application as initiators for polymerization reactions, e.g., silicone or polyester resins, in the making of fiberglass-reinforced composites. For these uses, the peroxides are typically in the form of a dilute solution in an organic solvent; methyl ethyl ketone peroxide is more common for this purpose, as it is stable in storage. Acetone peroxide is used as a flour bleaching agent to bleach and "mature" flour.
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Alkenyl peroxides decompose readily by homolytic O-O bond cleavage into two radicals, generating an oxyl radical and an alkenyloxyl- or α-oxo-alkyl radical. Decomposition of alkenyl peroxides by homolytic cleavage of the O-O bond The significant weakness of the O-O bond can be explained by formation of the resonance stabilized alkenyloxyl radical and the strong carbonyl bond, respectively.N. Sebbar, J. W. Bozzelli, H. Bockhorn, J. Phys. Chem. A 2004, 108, 8353–8366.
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Radiolysis of intracellular water by ionizing radiation creates peroxides, which are relatively stable precursors to hydroxyl radicals. 60%- 70% of cellular DNA damage is caused by hydroxyl radicals, yet hydroxyl radicals are so reactive that they can only diffuse one or two molecular diameters before reacting with cellular components. Thus, hydroxyl radicals must be formed immediately adjacent to nucleic acids in order to react. Radiolysis of water creates peroxides that can act as diffusable, latent forms of hydroxyl radicals.
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One of the common inhibitors of enzymatic activity (for PON 1 and PON 3) is lipid peroxides found in the plasma. Lipid peroxides can inhibit Paraoxonase activity as an arylesterase and antioxidant, though the specific inhibition is dependent on the type of lipid head group. An important implication of this fact is that, in decreasing the activity of PON1 and PON3, the productivity of preventing oxidation of LDL. Enzyme activity is also regulated by a substrate-dependent polymorphism that occurs at position 192.
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In the presence of peroxides, HBr adds to a given alkene in an anti-Markovnikov addition fashion.March Jerry; (1985). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, inc.
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This reasoning also applies to aryl peroxides. Both compound classes thus have significantly weaker O-O bonds than other peroxides.B. Schweitzer-Chaput, T. Kurtén, M. Klussmann, Angew. Chem. Int. Ed. 2015, 54, 11848–11851.
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If white paper is desired, bleaching uses peroxides or hydrosulfites to increase the brightness of the pulp. The bleaching methods are similar for mechanical pulp, but the goal is to make the fiber brighter.
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The Fenton reaction generates two types of oxidants, Type I and Type II. Type I oxidants are moderately sensitive to peroxides and ethanol. Type I and Type II oxidants preferentially cleave at the specific sequences.
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Fish can accumulate toxins such as mercury, dioxins, and polychlorinated biphenyls (PCBs), and spoiled fish oil may produce peroxides. There appears to be little risk of contamination by microorganisms, proteins, lysophospholipids, cholesterol, and trans-fats.
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The carbon-centred free radical thus formed is able to react with an oxygen molecule to form a peroxide compound. The process of peroxide formation is greatly accelerated by exposure to even low levels of light, but can proceed slowly even in dark conditions. Unless a desiccant is used which can destroy the peroxides, they will concentrate during distillation, due to their higher boiling point. When sufficient peroxides have formed, they can form a crystalline, shock-sensitive solid precipitate at the mouth of a container or bottle.
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Tetrafluoroethylene is a colorless, odorless gas. Like all unsaturated fluorocarbons, it is susceptible to nucleophilic attack. It is unstable towards decomposition to carbon and carbon tetrafluoride () and prone to form explosive peroxides in contact with air.
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Glutathione Peroxidase 1 () Peroxidases or peroxide reductases (EC number 1.11.1.x) are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides.
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Laporte to the rescue Chemistry & Industry, 18 January 1993 It went on to buy Aztec Peroxides Inc., a US peroxides business, in 1994Laporte buys Aztec from Phillips, sells powder coatings Chemical Week, 5 January 1994 and Inspec Group plc, suppliers of specialty chemicals, in 1998.Laporte plans to buy Inspec for $1bn Wall Street Journal, 1998 It sold its major divisions, some 55% of the business by revenue, to Kohlberg Kravis Roberts in 2000. These divisions (Pigments and Additives, Formulated Products & Compounds and Computers & Electronics) subsequently became known as Rockwood Holdings Inc.
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A number of tests can be used to detect the presence of a peroxide in an ether; one is to use a combination of iron(II) sulfate and potassium thiocyanate. The peroxide is able to oxidize the Fe2+ ion to an Fe3+ ion, which then forms a deep-red coordination complex with the thiocyanate. Peroxides may be removed by washing with acidic iron(II) sulfate, filtering through alumina, or distilling from sodium/benzophenone. Alumina does not destroy the peroxides but merely traps them, and must be disposed of properly.
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Mars has almost no ozone layer, unlike the Earth, so UV light sterilizes the surface and produces highly reactive chemicals such as peroxides that would oxidize any organic chemicals.Hartmann, W. 2003. A Traveler's Guide to Mars. Workman Publishing.
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Simulation of the toxicity of Bis(trifluoromethyl)peroxide has shown that organic peroxides can cause peripheral and centrilobular zonal hepatic necrosis, increased liver weight and hepatic enzymes and fatty changes in hepatocytes. This occurs in both humans and experimental animals.Floyd E.P. and Stokinger H.E.,Toxicity studies of certain organic peroxides and hydroperoxides.,American Industrial Hygiene Association Journal, Vol: 19, pp: 205-212, 1958 Bates N, Driver C.P., Bianchi A., Methyl ethyl ketone peroxide ingestion: toxicity and outcome in a 6-year old child., Pediatrics, Vol: 108, pp: 473-476, 2001 Karhunen P.J., Ojanpera I, Lalu K, Vuori E., Peripheral zonal hepatic necrosis caused by accidental ingestion of methyl ethyl ketone peroxide., Human and Experimental Toxicology, Vol: 9, pp: 197-200, 1990 The toxicity of peroxides is thought to be caused by the formation of reactive oxygen species (ROS) which are involved in lipid peroxidation further oxidative cellular damage.
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Ammonia causes the explosive polymerisation of ethylene oxide. It also forms explosive fulminating compounds with compounds of gold, silver, mercury, germanium or tellurium, and with stibine. Violent reactions have also been reported with acetaldehyde, hypochlorite solutions, potassium ferricyanide and peroxides.
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General structure of an alkenyl peroxide Alkenyl peroxides are chemical substances bearing an alkene residue directly at the peroxide group. They have very weak O-O bonds and are thus generally unstable compounds.M. Klussmann, Chem. Eur. J. 2018, 24, 4480–4496.
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Because of this weak bond, alkenyl peroxides are generally only postulated as reactive intermediates. An exception is the case of some few heteroarylperoxides, which were long-lived enough to be characterized.H. Kropf, M. Ball, Liebigs Ann. Chem. 1976, 2331–2338.
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Crosslinking mostly takes place via vulcanisation with sulphur, but is also accomplished with peroxides (for better heat resistance) or with phenolic resins. High energy radiation such as from electron beams is sometimes used for producing foams and wire and cable.
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Initiator is the more correct term. Cobalt salts are usually used as a true catalyst. Substances used are generally organic peroxides such as benzoyl peroxide or methyl ethyl ketone peroxide. Polyester resins are thermosetting and, as with other resins, cure exothermically.
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28 Day oral rat repeat dose studies with organic peroxides have shown alterations in rat kidneys in the form of histopathologic lesions. Further research of how this relates to bis(trifluoromethyl)peroxide is needed to draw conclusions from this, however.
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More specifically, it can form explosive peroxides when exposed to air and is extremely flammable. Also, it reacts violently with water. These make this reagent very dangerous to work with.Nysted Reagent. MSDS No.381985; Sigma-Aldrich; St. Louis, MO, April 3, 2009.
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Many hydrophosphination reactions are initiated by free-radicals. AIBN and peroxides are typical initiators, as well as Ultraviolet irradiation. In this way, the commercially important tributylphosphine and trioctylphosphine are prepared in good yields from 1-butene and 1-octene, respectively. Radical hydrophosphination.
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The use of acrylates, initially designed for radical curing initiated by ultra-violet (UV) light or electron beam (EB) radiation, is well established and increasingly popular in two non UV/EB reaction mechanisms: free radical crosslinking initiated by peroxides and Michael addition.
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Methylene blue is also a photosensitizer used to create singlet oxygen when exposed to both oxygen and light. It is used in this regard to make organic peroxides by a Diels-Alder reaction which is spin forbidden with normal atmospheric triplet oxygen.
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"Endolithic Microorganisms in the Antarctic Cold Desert". Science: 215. 1045–1052. Mars has almost no ozone layer, unlike the Earth, so UV light sterilizes the surface and produces highly reactive chemicals such as peroxides that would oxidize any organic chemicals.Hartmann, W. 2003.
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Autoxidation is any oxidation that occurs in presence of oxygen. The term is usually used to describe the degradation of organic compounds in air (as a source of oxygen). Autoxidation produces hydroperoxides and cyclic organic peroxides. These species can react further to form many products.
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GTPCH (GCH1) and tetrahydrobiopterin were found to have a secondary role protecting against cell death by ferroptosis in cellular models by limiting the formation of toxic lipid peroxides. Tetrahydrobiopterin acts as a potent, diffusable antioxidant that resists oxidative stress and enables cancer cell survival.
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This effect becomes drastically weaker for the larger sodium and potassium, allowing them to form the less stable peroxides. Rubidium and caesium, at the bottom of the group, are so large that even the least stable superoxides can form. Because the superoxide releases the most energy when formed, the superoxide is preferentially formed for the larger alkali metals where the more complex anions are not polarised. (The oxides and peroxides for these alkali metals do exist, but do not form upon direct reaction of the metal with oxygen at standard conditions.) In addition, the small size of the Li+ and O2− ions contributes to their forming a stable ionic lattice structure.
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10 peroxides, or moisture. This cross-linking creates the memory in the tubing so that it is able to shrink back to its original extruded dimensions upon heating, producing a material called heat-shrink tubing. For outdoor use, heat-shrink tubing often has a UV stabiliser added.
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Diethyl ether hydroperoxide is the organic compound with the formula C2H5OCH(OOH)CH3. It is a colorless, distillable liquid. Diethyl ether hydroperoxide and its condensation products are blamed for the explosive organic peroxides that slowly form upon exposure of diethyl ether to ambient air and temperature conditions.
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Organogallium compounds are also less reactive than organoaluminum compounds. They do form stable peroxides. These alkylgalliums are liquids at room temperature, having low melting points, and are quite mobile and flammable. Triphenylgallium is monomeric in solution, but its crystals form chain structures due to weak intermolecluar Ga···C interactions.
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The sulfate or sulphate (see spelling differences) ion is a polyatomic anion with the empirical formula . Sulfate is the spelling recommended by IUPAC, but sulphate is used in British English. Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life.
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The main cause of this condition is sun exposure. Hypersensitivity to the sun may be experienced due to genetic predisposition. It is also speculated that cosmetics and sun care products containing hydroxyl peroxides may trigger this condition through free radical and ultra violet A radiation photo-toxic reactions.
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Due to the likelihood of a fire from the decomposing organic peroxides, emergency personnel established a evacuation zone around the plant, and evacuated approximately 205 residents from this area. Notably, this evacuation area included U.S. Highway 90, one of the few major roads that remained not impacted by flooding.
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In comparison to other oxygen-centered oxidants (hypohalites, anions of peroxides) and in line with its low basicity, bromite is a rather weak nucleophile. Rate constants of bromite towards carbocations and acceptor- substituted olefins are by 1–3 orders of magnitude lower than the ones measured with hypobromite.
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Zinc peroxide (ZnO2) appears as a bright yellow powder at room temperature. It was historically used as a surgical antiseptic. More recently zinc peroxide has also been used as an oxidant in explosives and pyrotechnic mixtures. Its properties have been described as a transition between ionic and covalent peroxides.
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Marked alterations in neural membrane glycerophospholipid composition have been reported to occur in neurological disorders. These alterations result in changes in membrane fluidity and permeability. These processes along with the accumulation of lipid peroxides and compromised energy metabolism may be responsible for the neurodegeneration observed in neurological disorders.
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In perfumery, it is used as a fixative to lower the evaporation rate and improve stability. It is used industrially as a stabilizer to inhibit autopolymerization of organic peroxides. It is used as an antioxidant in biodiesel. It is also added to varnishes, lacquers, resins, and oil-field additives.
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Hydrogen peroxide is a weak acid, forming hydroperoxide or peroxide salts with many metals. It also converts metal oxides into the corresponding peroxides. For example, upon treatment with hydrogen peroxide, chromic acid ( + ) forms an unstable blue peroxide CrO(. This kind of reaction is used industrially to produce peroxoanions.
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Hydroperoxides can be reduced to alcohols with lithium aluminium hydride, as described in this idealized equation: :4 ROOH + LiAlH4 → LiAlO2 \+ 2 H2O + 4 ROH This reaction is the basis of methods for analysis of organic peroxides. Another way to evaluate the content of peracids and peroxides is the volumetric titration with alkoxides such as sodium ethoxide. The phosphite esters and tertiary phosphines also effect reduction: :ROOH + PR3 → OPR3 \+ ROH Hydroperoxides are intermediates in the production of many organic compounds in industry. For example, the cobalt catalyzed oxidation of cyclohexane to cyclohexanone: :C6H12 \+ O2 → (CH2)5CO + H2O Acetone and phenol are produced by the so-called cumene process, which proceeds via cumene hydroperoxide.
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Under controlled conditions, however, all the alkali metals, with the exception of francium, are known to form their oxides, peroxides, and superoxides. The alkali metal peroxides and superoxides are powerful oxidising agents. Sodium peroxide and potassium superoxide react with carbon dioxide to form the alkali metal carbonate and oxygen gas, which allows them to be used in submarine air purifiers; the presence of water vapour, naturally present in breath, makes the removal of carbon dioxide by potassium superoxide even more efficient. All the stable alkali metals except lithium can form red ozonides (MO3) through low-temperature reaction of the powdered anhydrous hydroxide with ozone: the ozonides may be then extracted using liquid ammonia.
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2-Ethylhexyl acrylate polymerizes easily. The polymerization can be initiated by light, peroxides, heat, or contaminants. It can react violently when combined with strong oxidants and can form explosive mixtures with air at temperatures above . The chemical, physical, and toxicological properties, however, can be greatly modified by additives or stabilizers.
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Lev Pisarzhevsky Lev Vladimirovich Pisarzhevsky (also transliterated as Pisarzhevskii: ; 13 February 1874 - 23 March 1938) was a Ukrainian Soviet chemist who studied peroxides, peracids, and solutions. His contribution to the theory of catalysis is best known for his attempt to relate the catalytic properties of solids to their electronic properties.
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O3F2 is a viscous, blood-red liquid. It remains liquid at 90 K and so can be differentiated from O2F2 which has a melting point of about 109 K.De Marco, Ronald A., and Jean'ne M. Shreeve . "Fluorinated Peroxides." Advances in Inorganic Chemistry and Radiochemistry. Vol. 16. Academic Press, 1974. 109-176.
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Ampyrone is a metabolite of aminopyrine with analgesic, anti-inflammatory, and antipyretic properties. Due to the risk of agranulocytosis its use as a drug is discouraged. It is used as a reagent for biochemical reactions producing peroxides or phenols. Ampyrone stimulates liver microsomes and is also used to measure extracellular water.
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Commercial paper indicators using this reaction are available. This method is also suitable for quantitative evaluation, but it can not distinguish between different types of peroxide compounds. Discoloration of various indigo dyes in presence of peroxides is used instead for this purpose.Veibel, S. Analytik organischer Verbindungen, Akademie-Verlag, Berlin, 1960, p.
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262 For example, the loss of blue color in leuco-methylene blue is selective for hydrogen peroxide. Quantitative analysis of hydroperoxides can be performed using potentiometric titration with lithium aluminium hydride. Another way to evaluate the content of peracids and peroxides is the volumetric titration with alkoxides such as sodium ethoxide.
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Diethyl ether peroxides can be detected with a potassium iodide (KI) solution in acetic acid or potassium iodide / starch paper. A positive test results in the formation of iodine (I2) that causes a yellow or brown color of the ether phase or a dark bluish spot on the paper strip.
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Purolator Inc. is a Canadian courier that is 91% owned by Canada Post, 7% owned by Rainmaker Investments Ltd. and 2% by others. Purolator truck showing the HAZMAT Class 5 Oxidizing Agents and Organic Peroxides placard on the rear door The company was originally organized as Trans Canada Couriers, Ltd.
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It produces good quality polymers which are quite stable. This property is the reason an economical synthesis is sought for BTP. This chemical is unusual in the fact that unlike many peroxides, bis(trifluoromethyl)peroxide is a gas, is nonexplosive and has good thermal stability.Ellingboe, E.K.; McCleiland A.L. Polymerization initiator.
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Cartoon representation of a complex between DNA and the protein p53 (described in Cho et al. Science 265 pp. 346, 1994) In 2008 Emekli-Alturfan, et al., compared saliva from breast cancer patients to that from healthy individuals and observed, notably, that breast cancer patients’ samples contained dysplastic cells and reduced lipid peroxides.
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Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour. It is mainly useful for the production of peroxides but is generally useful in other areas such as in the preparation of dyes, perfumes, pharmaceuticals, and resins.
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Concentrated benzoyl peroxide is potentially explosive like other organic peroxides, and can cause fires without external ignition. The hazard is acute for the pure material, so the compound is generally used as a solution or a paste. For example, cosmetics contain only a small percentage of benzoyl peroxide and pose no explosion risk.
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Addition of phosphine and phosphines to alkenes and alkynes Under free-radical conditions the P-H bonds of primary and secondary phosphines add across alkenes. Such reactions proceed with anti-Markovnikov regiochemistry. AIBN or organic peroxides are used as initiators. Tertiary phosphine oxides and sulfides can be reduced with chlorosilanes and other reagents.
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A ball-and-stick model of VO(acac)2 Vanadyl acetylacetonate is a blue complex with the formula V(O)(acac)2. This complex features the vanadyl(IV) group, and many related compounds are known. The molecule is square pyramidal, with idealized C2v symmetry. The complex catalyzes epoxidation of allylic alcohols by peroxides.
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Oct-1-en-3-one (CH2=CHC(=O)(CH2)4CH3), also known as 1-octen-3-one, is the odorant that is responsible for the typical "metallic" smell of metals and blood coming into contact with skin. Oct-1-en-3-one has a strong metallic mushroom-like odor with an odor detection threshold of 0.03–1.12 µg/m3 and it is the main compound responsible for the "smell of metal", followed by decanal (smell: orange skin, flowery) and nonanal (smell: tallowy, fruity).Supporting information for the Glindemann article Oct-1-en-3-one is the degradative reduction product of the chemical reaction of skin lipid peroxides and Fe2+. Skin lipid peroxides are formed from skin lipid by oxidation, either enzymatically by lipoxygenases or by air oxygen.
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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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Isopropyl alcohol vapor is denser than air and is flammable, with a flammability range of between 2 and 12.7% in air. It should be kept away from heat and open flame. Distillation of isopropyl alcohol over magnesium has been reported to form peroxides, which may explode upon concentration. Isopropyl alcohol is a skin irritant.
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2015 : in February the company finalized the purchase of Bostik from Total S.A.. The company also joined CJ Group of South Korea to invest in the manufacture of L-methionine in Malaysia. 2017 : During Hurricane Harvey, some organic peroxides burned in the Arkema Crosby TX plant, causing a 1.5 mile evacuation zone around the site.
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Oils with a high degree of unsaturation are most susceptible to autoxidation. The best test for autoxidation (oxidative rancidity) is determination of the peroxide value. Peroxides are intermediates in the autoxidation reaction. Autoxidation is a free radical reaction involving oxygen that leads to deterioration of fats and oils which form off-flavours and off-odours.
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Association of TBHP with the metal (M) generates the active metal peroxy complex containing the MOOR group, which then transfers an O center to the alkene. :Simplified mechanism for metal-catalyzed epoxidation of alkenes with peroxide (ROOH) reagents. Organic peroxides are used for the production of propylene oxide from propylene. Catalysts are required as well.
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Organic peroxides are often industrially used as oxidising agents. Exposure to such agents, for instance in the reported case of humans that were exposed to methyl ethyl ketone peroxide (MEKP), has been shown to cause peripheral zonal necrosis, increased hepatic enzyme levels and atypical pseudo-ductular proliferation at doses between 50 and 100 mL.
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Each oxygen atom in its peroxide ion may have a full octet of 4 pairs of electrons.Cook 1968, p.507 Superoxides are a class of compounds that are very similar to peroxides, but with just one unpaired electron for each pair of oxygen atoms (). These compounds form by oxidation of alkali metals with larger ionic radii (K, Rb, Cs).
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Possible hazards include implosions resulting from use of glassware that contains flaws, such as star-cracks. Explosions may occur from concentrating unstable impurities during evaporation, for example when rotavapping an ethereal solution containing peroxides. This can also occur when taking certain unstable compounds, such as organic azides and acetylides, nitro-containing compounds, molecules with strain energy, etc. to dryness.
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Nickel(III) oxides are often poorly characterized and are assumed to be nonstoichiometric compounds. Nickel(III) oxide (Ni2O3) has not been verified crystallographically. For applications in organic chemistry, nickel oxides or peroxides are generated in situ and lack crystallographic characterization. For example, "nickel peroxide" (CAS# 12035-36-8) is also closely related to or even identical with NiO(OH).
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The radicals formed from alkenyl peroxides can be utilized in organic radical reactions. For example, they can mediate hydrogen atom abstraction reactions and thus lead to the functionalization of C-H bonds,M. Klussmann, B. Schweitzer-Chaput, Synlett 2016, 27, 190-202. or they can be used to introduce ketone residues by addition of the alkenyloxyl radicals to alkenes.
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Antifreeze mixtures such as salts, peroxides, and perchlorates may allow fluid flow at Martian temperatures. Analogues of Mars landforms on Earth include Siberian and Hawaiian valleys, Greenland slopes, the Columbian Plateau, and various playas. Analogues for human expeditions (e.g. geology and hydrology fieldwork) include Devon Island, Canada, Antarctica, Utah, the Euro-Mars project, and Arkaroola, South Australia.
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Electron-deficient olefins, such as enones and acryl derivatives can be epoxidized using nucleophilic oxygen compounds such as peroxides. The reaction is a two-step mechanism. First the oxygen performs a nucleophilic conjugate addition to give a stabilized carbanion. This carbanion then attacks the same oxygen atom, displacing a leaving group from it, to close the epoxide ring.
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Bifenox is a protoporphyrinogen oxidase inhibitor and acts on the young parts, leaves, and partially on the roots of weeds and grasses. This leads to a release of peroxides that destroy the cell membranes of the weed plants and lead to tissue death. Bifenox also inhibits photosynthesis. The effect is enhanced by high light intensity and metabolic activity.
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It most often affects polyunsaturated fatty acids, because they contain multiple double bonds in between which lie methylene bridges (-CH2-) that possess especially reactive hydrogen atoms. As with any radical reaction, the reaction consists of three major steps: initiation, propagation, and termination. The chemical products of this oxidation are known as lipid peroxides or lipid oxidation products (LOPs).
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In 1990, Simons et al. isolated apocynin to a pharmacologically useful level using an actively guided isolation procedure. Apocynin's observed anti- inflammatory capabilities proved to be a result of its ability to selectively prevent the formation of free radicals, oxygen ions, and peroxides in the body. Apocynin has since been extensively studied to help determine its disease-fighting capabilities and applications.
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The suffix -ase is used in biochemistry to form names of enzymes. The most common way to name enzymes is to add this suffix onto the end of the substrate, e.g. an enzyme that breaks down peroxides may be called peroxidase; the enzyme that produces telomeres is called telomerase. Sometimes enzymes are named for the function they perform, rather than substrate, e.g.
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Thermal decomposition catalyzed by copper sulfate results in carbon dioxide and biacetal. 2,3,4-Pentanetrione reacts with hydrogen peroxide to yield acetic acid and carbon monoxide. Adding HOOH between C2 and C4 yields a cyclic intermediate which decomposes. With light or organic peroxides, a free radical reaction can take place (as with triketones), whereby the molecule is slit into CH3COCO• and CH3CO• fragments.
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The generation of heat in large quantities accompanies most explosive chemical reactions. The exceptions are called entropic explosives and include organic peroxides such as acetone peroxide. It is the rapid liberation of heat that causes the gaseous products of most explosive reactions to expand and generate high pressures. This rapid generation of high pressures of the released gas constitutes the explosion.
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The O−O bond length in peroxides is about 1.45 Å, and the R−O−O angles (R = H, C) are about 110° (water-like). Characteristically, the C−O−O−H dihedral angles are about 120°. The O−O bond is relatively weak, with a bond dissociation energy of , less than half the strengths of C−C, C−H, and C−O bonds.
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This accumulation of damage on the biological molecules changes the framework and leads to a reduction in the molecules' activity levels. Lipid peroxides accumulate in the membrane phospholipids, which in turn diminishes the mitochondrial membrane's effectiveness as a barrier. The process of DNA transcription and translation also acquires oxidative damage. The result is alterations in the base pairings of the DNA sequence.
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When thermal decomposition occurs some organic peroxide formulations release a considerable amount of gases and/or mists. Some, but not all, of these gases may be flammable. For example, carbon dioxide is a common, gaseous decomposition product for diacyl peroxides and peresters that is not flammable. The decomposition may include small organic fragments such as methane or acetone which are flammable.
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At 10:00am CDT, the National Hurricane Center updated its forecast, calling for an additional rainfall and up to over the next several days. Early in the day, the ride-out crew shut down electricity to several Low Temperature Warehouses. Organic peroxides in these warehouses were transferred into refrigerated trailers. The ride-out crew was optimistic that flooding would crest.
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Since pure chlorine is a toxic corrosive gas, these products usually contain hypochlorite, which releases chlorine when needed. "Bleaching powder" usually means a formulation containing calcium hypochlorite. Oxidizing bleaching agents that do not contain chlorine are usually based on peroxides such as hydrogen peroxide, sodium percarbonate, and sodium perborate. These bleaches are called 'non-chlorine bleach,' 'oxygen bleach' or 'color-safe bleach.
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Ascaridole is a colorless liquid that is soluble in most organic solvents. It is toxic and has a pungent, unpleasant smell and taste. Like other pure, low molecular weight organic peroxides, it is unstable and prone to explosion when heated to a temperature above 130 °C or treated with organic acids. When heated, it emits fumes which are poisonous and possibly carcinogenic.
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It is mainly used resins based on epoxy resin. Vinyl ester- based prepregs are also available. Since vinyl ester resins must be pre- accelerated with amine accelerator or cobalt, their processing time at room temperature is shorter than with epoxy-based prepregs. Catalysts (also called hardeners) include peroxides such as methyl ethyl ketone peroxide (MEKP), acetyl acetone peroxide (AAP) or cyclohexanone peroxide (CHP).
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In rice (Oryza sativa), for example, evidence suggests that the CCR1 homolog is an effector of Rac1, a small GTPase important for plant defense response. In this case, the Rac1 protein is proposed to activate CCR upon binding, leading to enhanced monolignol biosynthesis. Because Rac1 also activates NADPH oxidase, which produces peroxides critical for monolignol polymerization, overall lignin biosynthesis is enhanced as well.
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Oxygenated Lb2+ (Lb2+O2) readily autoxidizes to ferric Lb (Lb3+) generating O2− in the presence of trace amounts of transition metals, chelators and toxic metabolites (such as nitrite, superoxide radical and peroxides),Becana M.,Klucas R. V., Oxidation and reduction of leghemoglobin in root nodules of leguminous plants, Plant Physiol., 98 (1992) 1217-1221. however Lb2+ is the predominant form in nodules.
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The general structure of an organic peroxide The general structure of a perester Organic peroxides are organic compounds containing the peroxide functional group (ROOR′). If the R′ is hydrogen, the compounds are called organic hydroperoxides. Peresters have general structure RC(O)OOR. The O−O bond easily breaks, producing free radicals of the form RO• (the dot represents an unpaired electron).
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Barium peroxide is the inorganic compound with the formula BaO2. This white solid (gray when impure) is one of the most common inorganic peroxides, and it was the first peroxide compound discovered. Being an oxidizer and giving a vivid green colour upon ignition (as do all barium compounds), it finds some use in fireworks; historically, it was also used as a precursor for hydrogen peroxide.
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Greater amounts of oxygen can be provided by contacting the water with pure oxygen or addition of hydrogen peroxide (H2O2) to the water. In some cases, slurries of solid calcium or magnesium peroxide are injected under pressure through soil borings. These solid peroxides react with water releasing H2O2 which then decomposes releasing oxygen. Air sparging involves the injection of air under pressure below the water table.
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Thiourea reduces peroxides to the corresponding diols. The intermediate of the reaction is an unstable endoperoxide. reduction of cyclic peroxide Thiourea is also used in the reductive workup of ozonolysis to give carbonyl compounds. Dimethyl sulfide is also an effective reagent for this reaction, but it is highly volatile (boiling point ) and has an obnoxious odor whereas thiourea is odorless and conveniently non-volatile (reflecting its polarity).
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Anthrax spores can survive for very long periods of time in the environment after release. Chemical methods for cleaning anthrax-contaminated sites or materials may use oxidizing agents such as peroxides, ethylene oxide, Sandia Foam, chlorine dioxide (used in the Hart Senate Office Building),"The Anthrax Cleanup of Capitol Hill." Documentary by Xin Wang produced by the EPA Alumni Association. Video, Transcript (see p8).
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Artemisinin combination treatments (ACTs) are now widely used to treat uncomplicated falciparum malaria, but access to ACTs is still limited in most malaria-endemic countries and only a minority of the patients who need artemisinin-based combination treatments receive them. In 2008 White predicted that improved agricultural practices, selection of high-yielding hybrids, microbial production, and the development of synthetic peroxides would lower prices.
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The general structure of an organic hydroperoxide with the blue marked functional group Hydroperoxides or peroxols are compounds containing the hydroperoxide functional group (ROOH). If the R is organic, the compounds are called organic hydroperoxides. Such compounds are a subset of organic peroxides, which have the formula ROOR. Organic hydroperoxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds.
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Di-tert-butyl peroxide or DTBP is an organic compound consisting of a peroxide group bonded to two tert-butyl groups. It is one of the most stable organic peroxides, due to the tert-butyl groups being bulky. It is a colorless liquid.T. V. RajanBabu, Nigel S. Simpkins, T. V. RajanBabu "1,1-Di-tert-butyl Peroxide" in e-EROS Encyclopedia of Reagents for Organic Synthesis 2005.
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The reaction always involves at least two steps, and possibly a third. :Free-radical substitution general description In the first step called initiation (2,3) a free radical is created by homolysis. Homolysis can be brought about by heat or ultraviolet light but also by radical initiators such as organic peroxides or azo compounds. UV Light is used to create two free radicals from one diatomic species.
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Arkema operates a plant in Crosby, Texas, which flooded during Hurricane Harvey in August 2017. Arkema said it was unable to prevent the possibility of an explosion at the plant, after refrigeration equipment that kept temperature sensitive organic peroxides cold failed due to flooding. On August 31 explosions were reported to be coming from the plant, but these explosions were perhaps just "small container ruptures".
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The organic peroxides are stored in nine storage buildings. Seven of these buildings are Low Temperature Warehouses, kept at . One building is kept at ambient temperature and the largest storage building contained multiple compartments kept at various temperatures ranging from to ambient temperature. The Low Temperature Warehouses contain two refrigeration systems: mechanical refrigeration units, powered by electricity and a liquid nitrogen system not reliant on electricity.
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At 2:00am CDT, commercial power was lost, when transformers were flooded. The two remaining standby generators were activated to continue providing electricity to the last Low Temperature Warehouse. However, one of these generators was quickly flooded. At 3:00am CDT, the ride-out crew began transferring the organic peroxides in the last warehouse into two refrigerated trailers, fearing loss of the last remaining generator.
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Cyclopentyl methyl ether (CPME), also known as methoxycyclopentane, is hydrophobic ether solvent. A high boiling point of and preferable characteristics such as low formation of peroxides, relative stability under acidic and basic conditions, formation of azeotropes with water coupled with a narrow explosion range render CPME an alternative to other ethereal solvents such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), dioxane, and 1,2-dimethoxyethane (DME).
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Acetone peroxides are unwanted by-products of some oxidation reactions such as those used in phenol syntheses. Due to their explosive nature, their presence in chemical processes and chemical samples creates potential hazardous situations. Accidental occurrence at illicit MDMA laboratories is possible. Numerous methods are used to reduce their appearance, including shifting pH to more alkaline, adjusting reaction temperature, or adding inhibitors of their production.
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Thermate composition is a thermite one enriched with a salt- based oxidizer (usually nitrates, e.g., barium nitrate, or peroxides). In contrast with thermites, thermates burn with evolution of flame and gases. The presence of the oxidizer makes the mixture easier to ignite and improves penetration of target by the burning composition, as the evolved gas is projecting the molten slag and providing mechanical agitation.
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GPX1 is ubiquitously expressed in many tissues, where it protects cells from oxidative stress. Within cells, it localizes to the cytoplasm and mitochondria. As a glutathione peroxidase, GPx1 functions in the detoxification of hydrogen peroxide, specifically by catalyzing the reduction of hydrogen peroxide to water. The glutathione peroxidase also catalyzes the reduction of other organic hydroperoxides, such as lipid peroxides, to the corresponding alcohols.
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The "natural" substrates for PON1 appear to be lactones. However, PON1 has evolved to be a highly promiscuous enzyme capable of hydrolysing a wide variety of substrates such as lactones (including a number of important pharmaceutical agents such as statins), glucuronide drugs, thiolactones, arylesters, cyclic carbonates, organophosphorus pesticides and nerve gases such as sarin, soman and VX, oestrogen esters and lipid peroxides (oxidised lipids).
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Dibenzoyl peroxide is used as a radical initiator and to assist polymerization of acrylates. Industrial resins based on acrylic and/or methacrylic acid esters are invariably produced by radical polymerization with organic peroxides at elevated temperatures.Thomas Brock, Michael Groteklaes, Peter Mischke Lehrbuch der Lacktechnologie, Vincentz Network GmbH & Co KG, 2000, p. 67 The polymerization rate is adjusted by suitable choice of temperature and type of peroxide.
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Aside from ethylene oxide, most epoxides are generated by treating alkenes with peroxide-containing reagents, which donate a single oxygen atom. Safety considerations weigh on these reactions because organic peroxides are prone to spontaneous decomposition or even combustion. Metal complexes are useful catalysts for epoxidations involving hydrogen peroxide and alkyl hydroperoxides. Peroxycarboxylic acids, which are more electrophilic, convert alkenes to epoxides without the intervention of metal catalysts.
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The use of peroxyacids and peroxides when performing the Baeyer–Villiger oxidation can cause the undesirable oxidation of other functional groups. Alkenes and amines are a few of the groups that can be oxidized. For instance, alkenes in the substrate, particularly when electron-rich, may be oxidized to epoxides. However, methods have been developed that will allow for the tolerance of these functional groups.
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It is used in the production of various organic peroxides with dibenzoyl peroxide being a high volume example. It is used in polymerisations, as a flour bleaching agent, and as a treatment for acne. Peroxy acids, such as peracetic acid and meta-chloroperoxybenzoic acid also are produced using hydrogen peroxide. Hydrogen peroxide has been used for creating organic peroxide-based explosives, such as acetone peroxide.
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A Cetane Improver [′sē‚tān im′prüv·ər] is a chemical which has the effect of increasing a diesel fuel's Cetane number. A few examples are nitrates, nitroalkanes, nitrocarbonates and peroxides. One of the main Cetane Improver additives manufactured today is 2-ethylhexyl nitrate (CAS n°: 27247-96-7) which starts to decompose at 130 °C. 2-ethylhexyl nitrate is the result of the reaction of 2-ethylhexanol and nitric acid.
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Gauge station 1740 recorded a increase in the Cedar Bayou Stream's water level, during the day. Meanwhile, the ride-out crew monitored the facility. Towards the end of the day, they determined preempted electrical shutdowns would be needed to reduce danger of equipment damage and electrocution. During the evening, landline phones failed and water continued to rise, surrounding the Low Temperature Warehouses, where the organic peroxides were stored.
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Organic peroxides are typically explosive since they contain both the oxidizer, the O-O bond, and reducing agents, the C-C and C-H bonds. It is shock sensitive and explosive. The threshold quantity for Process Safety Management per Occupational Safety and Health Administration 1910.119 is if the concentration of the diacetyl peroxide solution is greater than 70%. There have been reports of detonation of the pure material.
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Lactoferrin's primary role is to sequester free iron, and in doing so remove essential substrate required for bacterial growth. Antibacterial action of lactoferrin is also explained by the presence of specific receptors on the cell surface of microorganisms. Lactoferrin binds to lipopolysaccharide of bacterial walls, and the oxidized iron part of the lactoferrin oxidizes bacteria via formation of peroxides. This affects the membrane permeability and results in the cell breakdown (lysis).
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Some substrates e.g. paraoxon are hydrolysed faster by the R- isoform while others such as diazoxon and lipid-peroxides are hydrolysed more rapidly by the Q- isoform. Both the coding region PON1-L55M and the promoter region PON1-T-108C polymorphisms are associated with different serum concentrations and therefore activities. The 55L allele results in significantly higher PON1 mRNA and serum protein levels and therefore activity compared to the 55M allele.
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Organic peroxides are useful in chemical synthesis due to their propensity to decompose. In doing so they generate useful radicals that can initiate polymerization to create polymers, modify polymers by grafting or visbreaking, or cross-link polymers to create a thermoset. When used for these purposes, the peroxide is highly diluted, so the heat generated by the exothermic decomposition is safely absorbed by the surrounding medium (e.g. polymer compound or emulsion).
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A related ring-opening reaction involves peroxides to give the useful peroxy acid: :C6H4(CO)2O + H2O2 → C6H4(CO3H)CO2H Phthalimide can be prepared by heating phthalic anhydride with aqueous ammonia giving 95–97% yield. Alternatively, it may be prepared by treating the anhydride with ammonium carbonate or urea. It can also be produced by ammoxidation of o-xylene. Potassium phthalimide is commercially available and is the potassium salt of phthalimide.
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The mechanism of action of cerumenolytics vary by the classification. Water-based cerumenolytics, including water itself, work by hydrating ear wax, fragmenting corneocytes (a type of skin cell) within the ear wax itself. Cerumenolytics with peroxides release oxygen upon contact with the skin, inducing effervescence (bubbling) that mechanically fragments ear wax. Oil-based cerumenolytics provide lubrication to the ear wax, softening the surface without fragmenting the ear wax.
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For example, vitamin E was found to counteract the formation of lipid peroxides induced by T-2 toxin in chickens. Similarly, cosupplementation of modified glucomannas and selenium in the diets of chickens also consuming T-2 toxin, reduced the deleterious effects of toxin associated depletion of antioxidants in the liver. Despite not being a direct antidote, these antioxidants may be critical in reducing the severity of trichothecene exposures.
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The Fenton reaction results in the creation of hydroxyl radicals from hydrogen peroxide and an Iron (II) catalyst. Iron(III) is regenerated via the Haber-Weiss reaction. Transition metals with a free coordination site are capable of reducing peroxides to hydroxyl radicals. Iron is believed to be the metal responsible for the creation of hydroxyl radicals because it exists at the highest concentration of any transition metal in most living organisms.
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Flammable aerosols can be classified as Class 1 or Class 2 if they contain any component, which is classified as flammable. # Oxidizing substances and organic peroxides contain • category 1: oxidizing substances and • category 2: organic peroxides, organic liquids or solids that contain the bivalent -O-O- structure and may be considered a derivative of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. The term also includes organic peroxide formulations (mixtures). Substances and mixtures of this hazard class are assigned to one of seven 'Types', A to G, on the basis of the outcome of the UN Test Series A to H. #Radioactive substances # Substances corrosive to metal are substances or mixtures that by chemical action will materially damage or even destroy metals. These substances or mixtures are classified in a single hazard category on the basis of tests (Steel: ISO 9328 (II): 1991 - Steel type P235; Aluminum: ASTM G31-72 (1990) - non-clad types 7075-T6 or AZ5GU-T66).
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Quartz is a common crystalline mineral made of silica, or silicon dioxide () The rest of the Earth's crust is formed also of oxygen compounds, most importantly calcium carbonate (in limestone) and silicates (in feldspars). Water-soluble silicates in the form of , , and are used as detergents and adhesives. Peroxides retain some of oxygen's original molecular structure ((−O-O−). White or light yellow sodium peroxide () is formed when metallic sodium is burned in oxygen.
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Vinyl ester resin, or often just vinyl ester, is a resin produced by the esterification of an epoxy resin with acrylic or methacrylic acids. The "vinyl" groups refer to these ester substituents, which are prone to polymerize. The diester product is then dissolved in a reactive solvent, such as styrene, to approximately 35–45 percent content by weight. Polymerization is initiated by free radicals, which are generated by UV-irradiation or peroxides.
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This compares to modern values less than 1 to 4. This bark, which must have been used as support as well as protection, probably had 38% to 58% lignin. Lignin is insoluble, too large to pass through cell walls, too heterogeneous for specific enzymes, and toxic, so that few organisms other than Basidiomycetes fungi can degrade it. To oxidize it requires an atmosphere of greater than 5% oxygen, or compounds such as peroxides.
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A hypothetical hydroxylation is shown in this illustration. After the product has been released from the active site, the enzyme returns to its original state, with a water molecule returning to occupy the distal coordination position of the iron nucleus. 300px # An alternative route for mono-oxygenation is via the "peroxide shunt" (path "S" in figure). This pathway entails oxidation of the ferric-substrate complex with oxygen-atom donors such as peroxides and hypochlorites.
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Additionally, catalase reduces mutations, whereas copper and nickel increase mutations by increasing reduction of peroxides. Some researchers believe that the oxidative stress on specific loci results in DNA polymerase pausing at those sites, creating an environment for DNA slippage to occur. Researchers first believed that MSI was random, but there is evidence suggesting that MSI targets include a growing list of genes. Examples include the transforming growth factor Beta receptor gene and the BAX gene.
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Selenenic acids derived from selenocysteine are involved in cell signaling and certain enzymatic processes. The best known selenoenzyme, glutathione peroxidase (GPx), catalyzes the reduction of peroxides by glutathione (GSH). The selenenic acid intermediate (E-SeOH) is formed upon oxidation of the catalytically active selenol (E-SeH) by hydrogen peroxide. This selenenic acid derivative of the peroxidase then reacts with a thiol-containing cofactor (GSH) to generate the key intermediate selenenyl sulfide (E-SeSG).
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The six trailers in the 'laydown area' were still intact. A survey flight conducted around 1:20pm CDT determined a trailer had lost its cooling capacity. Infrared images determined one of the trailers was leaking a substance that was at an elevated temperature, that was suspected to be a byproduct of decomposition of the organic peroxides. At 7:00pm CDT Unified Command and Arkema decided to carry out a controlled burn of the remaining trailers.
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A survey flight in the morning revealed more materials leaking from the trailers. Responders met at 10:00am CDT to reevaluate the plan, and ultimately decided to move forward with it. At 12:45 the plan was started, with an entry team confirming no leaking decomposed organic peroxides were near the isobutylene tank. It was confirmed the leaking material was not near the tank, and at 3:40pm CDT, the controlled burn was started.
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MTBE is extensively used in industry as a safer alternative to diethyl ether (which is commonly used in academic research) as the tert- butyl group prevents MTBE from forming potentially explosive peroxides. It also is used as a solvent in academic research, although it is used less commonly than diethyl ether. Although an ether, MTBE is a poor Lewis base and does not support formation of Grignard reagents. It is also unstable toward strong acids.
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121.1 (2004): 130-135. Organic peroxides of aluminium have explosive properties and can result in explosions with careless handling. An explosion of Octogen - Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and aluminium produce aluminium oxide (Al8/3O4).Kozak, G. D., Zhukov, I. S., Titova, U. O. Tsvigunov, A. N. “Analysis of solid explosion products of mixtures based on HMX and peroxide benzoyl with aluminum.” Combustion, Explosion, and Shock Waves. 46.5 (2010):589-592.
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Effervescent cleansers are the most popular immersion cleansers and include alkaline peroxides, perborates and persulphates. Their cleansing action occurs by the formation of small bubbles which displace loosely attached material from the surface of the denture. They are not very effective as cleansers and have a restricted ability to eliminate microbial plaque. Moreover, they are safe for use and do not cause deterioration of the acrylic resin or the metals used in denture construction.
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Benzoyl peroxide is also used as a radical initiator to induce chain-growth polymerization reactions, such as for polyester and poly(methyl methacrylate) (PMMA) resins and dental cements and restoratives. It is the most important among the various organic peroxides used for this purpose, a relatively safe alternative to the much more hazardous methyl ethyl ketone peroxide. It is also used in rubber curing and as a finishing agent for some acetate yarns.
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Although many different peroxyacids are used for the Baeyer–Villiger oxidation, some of the more common oxidants include meta-chloroperbenzoic acid (mCPBA) and trifluoroperacetic acid (TFPAA). The general trend is that higher reactivity is correlated with lower pKa (i.e.: stronger acidity) of the corresponding carboxylic acid (or alcohol in the case of the peroxides). Therefore, the reactivity trend shows TFPAA > 4-nitroperbenzoic acid > mCPBA and performic acid > peracetic acid > hydrogen peroxide > tert-butyl hydroperoxide.
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Dilution with a high-boiling solvent increases the SADT. The half-life of TBPB, in which 50% of the peroxy ester is decomposed, is 10 hours at 104 °C, one hour at 124 °C and one minute at 165 °C. Amines, metal ions, strong acids and bases, as well as strong reducing and oxidizing agents accelerate the decomposition of TBPB even in low concentrations. However, TBPB is one of the safest peresters or organic peroxides in handling.
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The resulting hydroxy radicals are often linked to DNA degradation, however, there are doubts as to whether or not this damage would be significant when analyzed in vivo since in vitro studies with both bovine and human serum albumin exhibited extensive protection against it. Myricetin's pro-oxidative capabilities can also be seen in its ability to act as an inhibitory agent against glutathione reductase, which is responsible for regenerating glutathione, a scavenger of free radicals and peroxides.
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Water (H2O) is the most familiar oxygen compound The oxidation state of oxygen is −2 in almost all known compounds of oxygen. The oxidation state −1 is found in a few compounds such as peroxides. Compounds containing oxygen in other oxidation states are very uncommon: − (superoxides), − (ozonides), 0 (elemental, hypofluorous acid), + (dioxygenyl), +1 (dioxygen difluoride), and +2 (oxygen difluoride). Oxygen is reactive and will form oxides with all other elements except the noble gases helium, neon, argon, and krypton.
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In response to an increased flux of hydrogen peroxide and other organic peroxides such as tert-butyl hydroperoxide and cumene hydroperoxide, peroxide stimulon gets activated. Studies of E. coli response to H2O2 have shown that exposure to H2O2 elevated mRNA levels of 140 genes, of which 30 genes are members of the OxyR regulon. The genes include many genes coding for metabolic enzymes and antioxidant enzymes demonstrating the role of these enzymes in reorganization of metabolism under stress conditions.
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The discovery of GSTK1 in the peroxisome has led to studies based on its function. It has been suggested that, similar to GSTA, GSTK1 may play a role in the buffering of acyl-CoA and xenobiotic-CoA and be involved in their binding activities. GSTK1 may also be responsible for the detoxification of lipid peroxides created in the peroxisome based on the peroxidase activity towards three substrates: tert-butyl hydroperoxide, cumene hydroperoxide, and 15-S-hydroperoxy-5,8,11,13-eicosatetraenoic acid.
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Bleaching is a process for whitening fabrics which has been practiced for thousands of years. Sometimes it was simply a matter of leaving the fabric in the sun, to be faded by the bright light. In the 18th century several scientists developed varieties of chlorine bleach, including sodium hypochlorite and calcium hypochlorite (bleaching powder). Bleaching agents that do not contain chlorine most often are based on peroxides, such as hydrogen peroxide, sodium percarbonate and sodium perborate.
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Isadore Perlman and William J. Knox, Jr., looked into peroxide separation because most elements form soluble peroxides in neutral or acid solution. They soon discovered that plutonium was an exception. After a good deal of experimentation, they found that they could precipitate it by adding hydrogen peroxide to a dilute uranyl nitrate solution. They were then able to get the process to work but it produced tons of precipitate, where the lanthanum fluoride process would produce kilograms.
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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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The scope of organoboranes and borates as reagents for organic synthesis is extremely wide. Reactions of organoboron compounds may produce alcohols, carbonyl compounds, halides, peroxides, amines, and other functionality depending on other starting materials employed and reaction conditions. This section covers a small subset of these methods, focusing on the synthesis of alcohols, carbonyl compounds, and halides. Alcohol synthesis from organoboranes and borates relies on either nucleophilic group transfer to a carbonyl group or oxidation of an intermediate organoborane.
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R. Gutbrod, R. N. Schindler, E. Kraka, D. Cremer, Chem. Phys. Lett. 1996, 252, 221–229,. They are formed via ozonolysis of alkenes in the atmosphere and form hydroxyl radicals upon decay, which play an important role in the decomposition of pollutants in the air. During day-time, hydroxyl radicals form predominantly photochemically by irradiation with light; whereas in the dark during night-time, the formation via alkenyl peroxides is believed to be their major source.
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Hydrogen peroxide, the simplest peroxide Since molecular oxygen can abstract H atoms from certain radicals, the HOO· radical is easily created. This particular radical can further abstract H atoms, creating H2O2, or hydrogen peroxide; peroxides can further cleave photolytically into two hydroxyl radicals. More commonly, HOO can react with free oxygen atoms to yield a hydroxy radical (·OH) and oxygen gas. In both cases, the ·OH radicals formed can serve to oxidize organic compounds in the atmosphere.
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It is used in air purifiers where weight is important, e.g., spacecraft to absorb carbon dioxide and release oxygen in the reaction: :2 Li2O2 \+ 2 CO2 → 2 Li2CO3 \+ O2 It absorbs more CO2 than does the same weight of lithium hydroxide and offers the bonus of releasing oxygen.Ulrich Wietelmann, Richard J. Bauer "Lithium and Lithium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH: Weinheim. Furthermore, unlike most other alkali metal peroxides, it is not hygroscopic.
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Nanotubes can also be alkylated with alkyl halides using lithium or sodium metal and liquid ammonia (Birch reduction conditions). The initial nanotube salt can function as a polymerization initiator and can react with peroxides to form alkoxy functionalized nanotubes The alkyl and hydroxyl modification of carbon nanotubes was demonstrated with the electrophilic addition of alkylhalides by microwave irradiation. Tessonnier et al. modified carbon nanotubes with amino groups by deprotonating with butyl lithium and reacting with amino substitution.
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Tetrahedron Letters, volume 30, issue 50, pages 6985-6988. A. J. Bloodworth and Neil A. Tallant (1992): "1,2,4-Trioxane versus 1,2-dioxolane formation in the mercury(II) acetate- mediated cyclisation of hemiperoxyacetals derived from allylic hydroperoxides". Journal of the Chemical Society, Chemical Communications,volume 1992, issue 5, Tsan H. Lay and Joseph W. Bozzelli (1997): "Enthalpies of formation of cyclic alkyl peroxides: dioxirane, 1,2-dioxetane, 1,2-dioxolane, and 1,2-dioxane". Chemical Physics Letters, volume 268, issues 1–2, pages 175-179.
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Oxidative stress mechanisms in tissue injury. Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination). Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal redox state of cells can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA.
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However, the presence of energetic free radicals during decomposition, particularly in hot gases or mists, can cause auto-ignition to occur at a lower temperature than would otherwise be normal for a similar chemical structure without the peroxy functional group. Organic peroxides do not generally consume oxygen as part of the decomposition so there is little risk of enhanced burning rates due to oxygen enrichment. This is unlike the decomposition of hydrogen peroxide and solid oxidizers that can liberate oxygen.
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While working at Goodyear, Spence altered the processes for vulcanization and the application of colored dyes to rubber. Traditionally, vulcanization was accomplished in air, with sulfur and other accelerators. While observing devulcanization, Spence noticed that the decomposition products were dependent on the oxygen content in the system, and that, without oxygen, the rubber failed to devulcanize. Based on these observations, Spence developed an oxygen, sulfur, and accelerator free vulcanization process by using organic oxidizers such as quinones or organic peroxides.
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Unlike lithium and sodium, however, potassium should not be stored under oil for longer than six months, unless in an inert (oxygen free) atmosphere, or under vacuum. After prolonged storage in air dangerous shock-sensitive peroxides can form on the metal and under the lid of the container, and can detonate upon opening. Ingestion of large amounts of potassium compounds can lead to hyperkalemia, strongly influencing the cardiovascular system. Potassium chloride is used in the United States for lethal injection executions.
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Ascaridole is a natural organic compound classified as a bicyclic monoterpenoids that has an unusual bridging peroxide functional group. It is a colorless liquid with a pungent smell and taste that is soluble in most organic solvents. Like other low molecular weight organic peroxides, it is unstable and prone to explosion when heated or treated with organic acids. Ascaridole determines the specific flavor of the Chilean tree boldo and is a major constituent of the oil of Mexican tea (wormseed).
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Ethane can be viewed as two methyl groups joined, that is, a dimer of methyl groups. In the laboratory, ethane may be conveniently synthesised by Kolbe electrolysis. In this technique, an aqueous solution of an acetate salt is electrolysed. At the anode, acetate is oxidized to produce carbon dioxide and methyl radicals, and the highly reactive methyl radicals combine to produce ethane: : CH3COO− → CH3• + CO2 \+ e− : CH3• + •CH3 → C2H6 Synthesis by oxidation of acetic anhydride by peroxides, is conceptually similar.
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The peroxide value is determined by measuring the amount of iodine which is formed by the reaction of peroxides (formed in fat or oil) with iodide ion. 2 I− \+ H2O + HOOH -> HOH + 2OH− \+ I2 The base produced in this reaction is taken up by the excess of acetic acid present. The iodine liberated is titrated with sodium thiosulphate. 2S2O32− \+ I2 -> S4O62− \+ 2 I− The acidic conditions (excess acetic acid) prevents formation of hypoiodite (analogous to hypochlorite), which would interfere with the reaction.
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Rubidium reacts violently with water and can cause fires. To ensure safety and purity, this metal is usually kept under dry mineral oil or sealed in glass ampoules in an inert atmosphere. Rubidium forms peroxides on exposure even to a small amount of air diffused into the oil, and storage is subject to similar precautions as the storage of metallic potassium. Rubidium, like sodium and potassium, almost always has +1 oxidation state when dissolved in water, even in biological contexts.
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The octahydrate is produced by treating sodium hydroxide with hydrogen peroxide. Sodium peroxide can be prepared on a large scale by the reaction of metallic sodium with oxygen at 130–200 °C, a process that generates sodium oxide, which in a separate stage absorbs oxygen:Macintyre, J. E., ed. Dictionary of Inorganic Compounds, Chapman & Hall: 1992.E. Dönges "Lithium and Sodium Peroxides" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 979.
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On October 31, 1992, the DEA conducted a drug raid at the Zschiegner Refining Company. The DEA initially conducted this raid due to suspicions that the ZRC were manufacturing illegal drugs. Not only did the DEA find that the company was manufacturing methamphetamine, but they also found approximately 3,000 different chemicals including peroxides, cyanides, caustics, and acids improperly stored at the facility. As a result, to this discovery, owner/operator Herbert Zschiegner was arrested for the illegal manufacture of methamphetamine.
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The earliest noted development of the tract of land was in 1956, when the land was christened as a 23.5 acre chemical manufacturing plant. The manufacturing plant produced various chemicals for Reichhold Chemicals, generally peroxides, for the majority of its 29 years as a chemical plant. The facility was closed following a series of on-site safety incidents in December, 1985, which made it economically infeasible to operate. The land was annexed into the Austin city limits on July 19, 1973.
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The hydrophobic tails are usually fatty acids that differ in lengths. The interactions of lipids, especially the hydrophobic tails, determine the lipid bilayer physical properties such as fluidity. Membranes in cells typically define enclosed spaces or compartments in which cells may maintain a chemical or biochemical environment that differs from the outside. For example, the membrane around peroxisomes shields the rest of the cell from peroxides, chemicals that can be toxic to the cell, and the cell membrane separates a cell from its surrounding medium.
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A similar accident killed Soviet cosmonaut Valentin Bondarenko in 1961. Combustion hazards also apply to compounds of oxygen with a high oxidative potential, such as peroxides, chlorates, nitrates, perchlorates, and dichromates because they can donate oxygen to a fire. Concentrated will allow combustion to proceed rapidly and energetically. Steel pipes and storage vessels used to store and transmit both gaseous and liquid oxygen will act as a fuel; and therefore the design and manufacture of systems requires special training to ensure that ignition sources are minimized.
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At Giessen, he did original analysis of beeswax for which he was given the Fellowship of the Royal Society in 1849 and awarded the Royal Medal in 1850. Brodie did important original work on peroxides in his private laboratory where he taught Nevil Story Maskelyne chemistry. He was secretary of the Chemical Society from 1850 to 1854 and its president in 1860. However, he opposed the atomic theory and proposed in 1866 his Calculus of Chemical Operations as a non-atomic alternative to the atomic theory.
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The gaseous methyl radicals are moved to another part of the chamber in a carrier gas where they react with lead in a mirror film which slowly disappears. When radical reactions are part of organic synthesis the radicals are often generated from radical initiators such as peroxides or azobis compounds. Many radical reactions are chain reactions with a chain initiation step, a chain propagation step and a chain termination step. Reaction inhibitors slow down a radical reaction and radical disproportionation is a competing reaction.
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It was precisely during the Geneva period of his life that Bach developed his peroxide theory of respiratory processes and took active part in Swiss scientific activities. Swiss scientists showed respect for Bach: the Geneva Society of Physical and Natural Sciences elected him its chairman for the year 1916. built up an international reputation in medical and agricultural chemistry for his research on catalysis and photosynthesis. Bach's scientific focus was the study of the assimilation of carbon dioxide as well as the mechanism of oxidation to peroxides.
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It is also used in peroxide bleaching to prevent degradation of peroxides by transition metals. Etidronic acid is listed as an ingredient of several cosmetic formulations where it is used for suppressing radical formation, emulsion stabiliser and viscosity control. While etidronic acid has not been limited from inclusion in cosmetics and does have legitimate uses, it is recommended that, as with most cosmetic products (particularly soaps), the product should be thoroughly rinsed from the skin after use. Etidronic acid is also included among swimming pool chemicals.
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Studies have found an association between denture stomatitis, colonization of yeasts and denture cleanliness . Another study found that immersing dentures in 0.5% NaOCl solution for 3 minutes only can be an effective synergic for denture cleaning in reducing the number of microorganism without affecting the denture colour or surface roughness , and when compared to alkaline peroxides, NaOCl was more efficient . Some clinicians recommended that the time of immersion, and the concentration of the NaOCl should be well considered so as not to degrade the acrylic resin of the denture.
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The detoxification of endogenous reactive metabolites such as peroxides and reactive aldehydes often cannot be achieved by the system described above. This is the result of these species' being derived from normal cellular constituents and usually sharing their polar characteristics. However, since these compounds are few in number, it is possible for enzymatic systems to utilize specific molecular recognition to recognize and remove them. The similarity of these molecules to useful metabolites therefore means that different detoxification enzymes are usually required for the metabolism of each group of endogenous toxins.
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Tires are made from many chemicals and compounds such as black carbon, sulphur, zinc oxide and peroxides. The US National Artificial Reef Plan states that tires are a good reef construction material because no toxic substances are released from the decomposition of tires; though there is little information published to back up the claims and the future decomposing of the many different types of rubber tires could create unseen pollution.Collins, K. J., Jensen, A. C., Mallinson, J. J., Roenelle, V., & Smith, I. P. (2002). Environmental impact assessment of a scrap tire artificial reef.
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Sodium amide reacts violently with water to produce ammonia and sodium hydroxide and will burn in air to give oxides of sodium and nitrogen dioxide. :NaNH2 \+ H2O → NH3 \+ NaOH :4 NaNH2 \+ 7 O2 → 2 Na2O + 4 NO2 \+ 4 H2O In the presence of limited quantities of air and moisture, such as in a poorly closed container, explosive mixtures of peroxides may form. This is accompanied by a yellowing or browning of the solid. As such, sodium amide is to be stored in a tightly closed container, under an atmosphere of an inert gas.
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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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Moreover, arsenic could cause oxidative stress by depleting the cell's antioxidants, especially the ones containing thiol groups. The accumulation of ROS like the cited above and hydroxyl radicals, superoxide radicals and hydrogen peroxides causes aberrant gene expression at low concentrations and lesions of lipids, proteins and DNA in higher concentrations which eventually lead to cellular death. In a rat animal model, urine levels of 8-hydroxy-2’-deoxyguanosine (as a biomarker of ROS DNA damage) were measured after treatment with DMA(V). In comparison to control levels, they turned out to be significantly increased.
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This regiochemistry follows from the reaction mechanism, which favors formation of the most stable carbon radical intermediate (relative stability: 3° > 2° > 1°> methyl). The mechanism for this reaction is similar to a chain reaction such as free radical halogenation in which the peroxide promotes the formation of the bromide radical. Therefore, in the presence of peroxides, HBr adds so that the bromine atom is added to the carbon bearing the most numerous hydrogen substituents and hydrogen atoms will add to carbons bearing fewest hydrogen substituents. However, this process is restricted to addition of HBr.
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All the alkali metals react vigorously with oxygen at standard conditions. They form various types of oxides, such as simple oxides (containing the O2− ion), peroxides (containing the ion, where there is a single bond between the two oxygen atoms), superoxides (containing the ion), and many others. Lithium burns in air to form lithium oxide, but sodium reacts with oxygen to form a mixture of sodium oxide and sodium peroxide. Potassium forms a mixture of potassium peroxide and potassium superoxide, while rubidium and caesium form the superoxide exclusively.
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The formation of gums is accelerated by copper salts, which can be neutralized by additives called metal deactivators. This degradation can be prevented through the addition of 5–100 ppm of antioxidants, such as phenylenediamines and other amines. Hydrocarbons with a bromine number of 10 or above can be protected with the combination of unhindered or partially hindered phenols and oil-soluble strong amine bases, such as hindered phenols. "Stale" gasoline can be detected by a colorimetric enzymatic test for organic peroxides produced by oxidation of the gasoline.
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Given appropriate conditions, methane reacts with halogen radicals as follows: :X• + CH4 → HX + CH3• :CH3• + X2 → CH3X + X• where X is a halogen: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This mechanism for this process is called free radical halogenation. It is initiated when UV light or some other radical initiator (like peroxides) produces a halogen atom. A two-step chain reaction ensues in which the halogen atom abstracts a hydrogen atom from a methane molecule, resulting in the formation of a hydrogen halide molecule and a methyl radical (CH3•).
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On the other hand, it catalyzes the oxidation of alkanes to tertiary alcohols, amides to t-butyldioxyamides, and tertiary amines to α-(t-butyldioxyamides) using tert-butyl hydroperoxide. Using other peroxides, oxygen, and acetone, the catalyst can oxidize alcohols to aldehydes or ketones. Using dichlorotris(triphenylphosphine)ruthenium(II) the N-alkylation of amines with alcohols is also possible (see "borrowing hydrogen"). :650px RuCl2(PPh3)3 efficiently catalyzes carbon-carbon bond formation from cross couplings of alcohols through C-H activation of sp3 carbons in the presence of a Lewis acid.
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Furthermore, it acts in a fully reversible manner, readily converting 5-oxo- ETE back to 5(S)-HETE. Since cells typically maintain very high levels of NADPH compared to their NADP+ levels, they generally have little or no ability to convert 5(S)-HEE to 5-oxo-ETE, and when confronted with 5-oxo-ETE rapidly metabolize it to 5(S)-HETE. However, cells undergoing aging, senescence, apoptosis, oxidative stress, or other conditions that raise their levels of reactive oxygen species (e.g. superoxide anion, oxygen radicals, and peroxides) either physiologically (e.g.
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The antioxidant effects of uric acid have led researchers to suggest this mutation was beneficial to early primates and humans. Studies of high altitude acclimatization support the hypothesis that urate acts as an antioxidant by mitigating the oxidative stress caused by high-altitude hypoxia. Uric acid has the highest concentration of any blood antioxidant and provides over half of the total antioxidant capacity of human serum. Uric acid's antioxidant activities are also complex, given that it does not react with some oxidants, such as superoxide, but does act against peroxynitrite, peroxides, and hypochlorous acid.
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Additional compounds have been produced by reacting NpO3 and water with solid alkali and alkaline peroxides at temperatures of 400 - 600 °C for 15–30 hours. Some of these include Ba3(NpO5)2, Ba2NaNpO6, and Ba2LiNpO6. Also, a considerable number of hexavelant neptunium oxides are formed by reacting solid-state NpO2 with various alkali or alkaline earth oxides in an environment of flowing oxygen. Many of the resulting compounds also have an equivalent compound that substitutes uranium for neptunium. Some compounds that have been characterized include Na2Np2O7, Na4NpO5, Na6NpO6, and Na2NpO4.
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In particular, one major contributor to oxidative damage is hydrogen peroxide (H2O2), which is converted from superoxide that leaks from the mitochondria. Catalase and superoxide dismutase ameliorate the damaging effects of hydrogen peroxide and superoxide, respectively, by converting these compounds into oxygen and hydrogen peroxide (which is later converted to water), resulting in the production of benign molecules. However, this conversion is not 100% efficient, and residual peroxides persist in the cell. While ROS are produced as a product of normal cellular functioning, excessive amounts can cause deleterious effects.
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The removal of dying cells is, to a greater extent, handled by fixed macrophages, which will stay at strategic locations such as the lungs, liver, neural tissue, bone, spleen and connective tissue, ingesting foreign materials such as pathogens and recruiting additional macrophages if needed. When a macrophage ingests a pathogen, the pathogen becomes trapped in a phagosome, which then fuses with a lysosome. Within the phagolysosome, enzymes and toxic peroxides digest the pathogen. However, some bacteria, such as Mycobacterium tuberculosis, have become resistant to these methods of digestion.
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The earlier relative of EPDM is EPR, ethylene propylene rubber, that contains no diene units and can only be crosslinked using radical methods such as peroxides. Dienes used in the manufacture of EPDM rubbers are ethylidene norbornene (ENB), dicyclopentadiene (DCPD), and vinyl norbornene (VNB). EPDM is derived from polyethylene into which 45-85 wt% of propylene have been copolymerised to reduce the formation of the typical polyethylene crystallinity. EPDM is a semi-crystalline material with ethylene-type crystal structures at higher ethylene contents, becoming essentially amorphous at ethylene contents that approach 50 wt%.
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The original 1858 synthesis by Liebig reacted benzoyl chloride with barium peroxide, a reaction that probably follows this equation: :2 C6H5C(O)Cl + BaO2 → (C6H5CO)2O2 \+ BaCl2 Benzoyl peroxide is usually prepared by treating hydrogen peroxide with benzoyl chloride. :2 C6H5COCl + H2O2 \+ 2 NaOH → (C6H5CO)2O2 \+ 2 NaCl + 2 H2O The oxygen–oxygen bond in peroxides is weak. Thus, benzoyl peroxide readily undergoes homolysis (symmetrical fission), forming free radicals: :(C6H5CO)2O2 → 2 The symbol • indicates that the products are radicals; i.e., they contain at least one unpaired electron.
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The net reaction in this case is then: :CO + 2 → + The amount of ozone produced through these reactions in ambient air can be estimated using a modified Leighton relationship. The limit on these interrelated cycles producing ozone is the reaction of •OH with NO2 to form nitric acid at high NOx levels. If nitrogen monoxide (NO) is instead present at very low levels in the atmosphere (less than 10 approximately ppt), the peroxy radicals (HO2• ) formed from the oxidation will instead react with themselves to form peroxides, and not produce ozone.
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Oxovanadium(V) also forms 7 coordinate coordination complexes with tetradentate ligands and peroxides and these complexes are used for oxidative brominations and thioether oxidations. The coordination chemistry of V4+ is dominated by the vanadyl center, VO2+, which binds four other ligands strongly and one weakly (the one trans to the vanadyl center). An example is vanadyl acetylacetonate (V(O)(O2C5H7)2). In this complex, the vanadium is 5-coordinate, square pyramidal, meaning that a sixth ligand, such as pyridine, may be attached, though the association constant of this process is small.
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Posner was first known for his pioneering research in organocopper chemistry in which he developed novel methods for organic synthesis involving organocopper reagents. He is the author of the textbook An Introduction to Synthesis Using Organocopper Reagents. Posner has also contributed numerous other developments in synthetic organic chemistry including asymmetric synthesis and multicomponent organic reactions. Posner’s recent research has been focused on applying organic synthesis to the preparation of novel medicinal agents including isothiocyanates with anticancer properties, new vitamin D analogs for the treatment of psoriasis, and new antimalarial peroxides.
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In some regions (e.g. much of the northeastern and northwestern US and adjacent Canada, and the southeastern US), selenium deficiency in some animal species is common unless supplementation is carried out. Selenium deficiency is responsible (either alone or together with vitamin E deficiency) for many of the cases of WMD ("white muscle disease"), evidenced at slaughter or during necropsy by whitish appearance of striated muscle tissue due to bleaching by peroxides and hydroperoxides. Although this degenerative disease can occur in foals, pigs and other animal species, ruminants are particularly susceptible.
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This reagent is a good formylating agent and can regenerate the unsubstituted imidazole (with formation of carbon monoxide) upon heating. Yet another reaction involves the acylation of triphenylalkelynephosphoranes. ::(C6H5)3P=CHR + R'-CO-Im → (C6H5)3P+-CHR-COR' + Im− (C6H5)3P+-CHR-COR' + (C6H5)3P=CHR → (C6H5)3P=CR-COR' + (C6H5)3P+-CH2R These can undergo the Wittig reaction to form α,β unsaturated ketones or aldehydes. The reagent can even undergo reaction with peroxide to form the peroxycarboxylic acid, which can react further to form diacyl peroxides.
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Peroxides can be produced when fish oil spoils. A study commissioned by the government of Norway concluded there would be some health concern related to the regular consumption of oxidized (rancid) fish/marine oils, particularly in regards to the gastrointestinal tract, but there is not enough data to determine the risk. The amount of spoilage and contamination in a supplement depends on the raw materials and processes of extraction, refining, concentration, encapsulation, storage and transportation. ConsumerLab.com reports in its review that it found spoilage in test reports it ordered on some fish oil supplement products.
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The sulfates are excreted in the urine. Due to its effects similar to nitric oxide (without its potential to form peroxides by interacting with superoxide), hydrogen sulfide is now recognized as potentially protecting against cardiovascular disease. The cardioprotective role effect of garlic is caused by catabolism of the polysulfide group in allicin to , a reaction that could depend on reduction mediated by glutathione. Though both nitric oxide (NO) and hydrogen sulfide have been shown to relax blood vessels, their mechanisms of action are different: while NO activates the enzyme guanylyl cyclase, activates ATP- sensitive potassium channels in smooth muscle cells.
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Nerve growth factor (50 ng/ml) induced functional differentiation in PC12 cells has been reported. The studies have been carried out showing mitochondria mediated apoptosis in PC12 cells exposed to monocrotophos. A significant induction in reactive oxygen species, lipid peroxides, and the ratio of glutathione disulfide/reduced glutathione was observed in cells exposed to selected doses of monocrotophos. Following the exposure of PC12 cells to monocrotophos, the levels of protein and mRNA expression of caspase-3, caspase-9, BAX, p53, p21, PUMA, and cytochrome-c were significantly upregulated, whereas the levels of Bcl-2, Bcl-w, and Mcl-1 were downregulated.
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Ferroptosis is a type of programmed cell death dependent on iron and characterized by the accumulation of lipid peroxides, and is genetically and biochemically distinct from other forms of regulated cell death such as apoptosis. Ferroptosis is initiated by the failure of the glutathione- dependent antioxidant defenses, resulting in unchecked lipid peroxidation and eventual cell death. Lipophilic antioxidants and iron chelators can prevent ferroptotic cell death. Although the connection between iron and lipid peroxidation has been appreciated for years, it was not until 2012 that Brent Stockwell and Scott Dixon coined the term ferroptosis and described several of its key features.
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Recently, a second parallel protective pathway was independently discovered by two labs that involves the oxidoreductase FSP1/AIFM2. Their findings indicate that FSP1/AIFM2 enzymatically reduces non- mitochondrial Coenzyme Q10, thereby generating a potent lipophilic antioxidant to suppresses the propagation of lipid peroxides. A similar mechanism for a cofactor moonlighting as a diffusable antioxidant was discovered in the same year for tetrahydrobiopterin/BH4, a product of the rate limiting enzyme GCH1. Human prostate cancer cells undergoing ferroptosis Small molecules such as erastin, sulfasalazine, sorafenib, altretamine, RSL-3, ML-162 and ML-210 are known inhibitors of this tumor cell growth and induce ferroptosis.
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When flammable gases or mists are released as part of the decomposition there is always the potential danger of a fire or vapor phase explosion. Therefore, the risk of vapor phase explosion should be kept in mind when designing storage structures. These types of materials may be released at low rates during storage and in quite high rates in the event of an upset due to failure to control storage temperature or in the event of a fire in the storage area. It is the ease of splitting the peroxy group to give two free radicals that makes organic peroxides so useful.
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A strong research focus has been placed on triggering production of excessive reactive oxygen species (ROS) using nanoparticles injected into bacterial cells. The presence of excessive ROS can stress the cell structure leading to damaged DNA/RNA, decreased membrane activity, disrupted metabolic activity, and harmful side reactions generating chemicals such as peroxides. ROS production has been induced generally through the introduction of both metal oxide and positively charged metal nanoparticles in the cell, such as iron oxides and silver. The positive charge of the metal is attracted to the negative charge of the cell membrane which it then easily penetrates.
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Revisions to weather forecasts raised the expected rainfall to with some areas seeing rainfall amounts of . With flooding of local roads now certain, the ride-out crew was activated. Staff were still confident the facility would have no issues with maintaining refrigeration of organic peroxides on site. During the day, production was discontinued, and staff prepared the facility for Harvey's arrival, securing loose materials, moving portable equipment that could be damaged by flooding, preparing storm equipment, such as an off-road forklift, ensuring fuel tanks were filled and reducing waste water levels in expectation of the significant rain.
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These actions are represented in their diagram of the "Hierarchy of Controls" shown below with the most effective steps at the top and the least effective at the bottom. The high vaporization potential and flammability of chloroprene has significant implications for handling and storage operations in the occupational setting. Chloroprene should be stored in closed containers in a cool, well-ventilated area with the temperature no higher than 50 degrees Fahrenheit. In addition, chloroprene has a high reactivity and should be stored away from oxidizing agents such as perchlorate, peroxides, permanganates, chlorates, nitrates, chlorine, bromine, and fluorine.
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Bacillithiol appears to participate in the sensing of peroxides by Bacillus, but may also substitute for glutathione, which is the most common intracellular thiol in eukaryotes and some bacteria. Some of the genes involved in the biosynthesis of bacillithiol were identified and characterized in 2010. Bacteria engineered to be deficient in bacillithiol demonstrated increased sensitivity to various electrophilic xenobiotic compounds, including the antibiotic fosfomycin, suggesting that in these organisms the mechanism of fosfomycin resistance relies on the presence of bacillithiol. Furthermore, in vitro kinetic studies have established that bacillithiol is a preferred thiol substrate for the antibiotic resistance enzyme FosB.
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Glutathione disulfide (GSSG) is a disulfide derived from two glutathione molecules. In living cells, glutathione disulfide is reduced into two molecules of glutathione with reducing equivalents from the coenzyme NADPH. This reaction is catalyzed by the enzyme glutathione reductase. Antioxidant enzymes, such as glutathione peroxidases and peroxiredoxins, generate glutathione disulfide during the reduction of peroxides such as hydrogen peroxide (H2O2) and organic hydroperoxides (ROOH): :2 GSH + ROOH → GSSG + ROH + H2O Other enzymes, such as glutaredoxins, generate glutathione disulfide through thiol-disulfide exchange with protein disulfide bonds or other low molecular mass compounds, such as coenzyme A disulfide or dehydroascorbic acid.
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Nevertheless, this may be misleading, since the harm presented by many of these chemicals (either natural or synthetic) is dependent on environmental conditions and their concentrations in a perfume. For instance, linalool, which is listed as an irritant, causes skin irritation when it degrades to peroxides, however the use of antioxidants in perfumes or reduction in concentrations can prevent this. As well, the furanocoumarin present in natural extracts of grapefruit or celery can cause severe allergic reactions and increase sensitivity to ultraviolet radiation. Some research on natural aromatics have shown that many contain compounds that cause skin irritation.
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The reaction of HBr with substituted alkenes was prototypical in the study of free-radical additions. Early chemists discovered that the reason for the variability in the ratio of Markovnikov to anti-Markovnikov reaction products was due to the unexpected presence of free radical ionizing substances such as peroxides. The explanation is that HBr produces a Br radical, which then reacts with the double bond. Since the bromine atom is relatively large, it is more likely to encounter and react with the least substituted carbon since this interaction produces less static interactions between the carbon and the bromine radical.
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One of the oxygen atoms in each peroxide group is considered "active". The theoretical amount of active oxygen can be described by the following equation: : A[O]theoretical (%) = 16 × 100, where p is the number of peroxide groups in the molecule, and m is the molecular mass of the pure peroxide. Organic peroxides are often sold as formulations that include one or more phlegmatizing agents. That is, for safety sake or performance benefits the properties of an organic peroxide formulation are commonly modified by the use of additives to phlegmatize (desensitize), stabilize, or otherwise enhance the organic peroxide for commercial use.
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Organic peroxides, such as methyl ethyl ketone peroxide and auxiliary accelerators which promote decomposition to form radicals are combined with the resin to initiate a room temperature cure. Unsaturated polyester resin synthetic pathway and structure In the liquid state, unsaturated polyester resins may be processed by numerous methods, including Hand Layup, vacuum bag molding, and spray-up and compression molded Sheet Molding Compound (SMC). They can also be B-staged after application to chopped reinforcement and continuous reinforcement, to form pre-pregs. Solid molding compounds in the form of pellets or granules are also used in processes such as compression and transfer molding.
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This is referred to as air inhibition and is a diffusion-controlled reaction with rates typically in the order of 107–109 mol−1 s−1, the resulting peroxy radicals (ROO•) are less reactive towards polymerisation. However air stabilisation is not suitable for monomers with which it can form explosive peroxides, such as vinyl chloride. Other stable radicals include TEMPO and TEMPOL, which are exceedingly effective radical scavengers. Certain compounds marketed as true inhibitors, such as p-phenylenediamines, phenothiazine and hydroxylamines like HPHA and DEHA, are also thought to react through the intermediary of aminoxyl radicals.
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Food and Chemical Toxicology, Vol: 38, pp: 411-416, 2000 Past animal studies have shown good correlations between organic peroxide damage in human case reports and test animals. 28-day repeat- dose studies of 1,1-bis (tert-butyldioxy)-3,3,5-trimethylcyclohexane and dicumyl peroxide [MHLW 2001a and b] in rats showed liver weight increase, periportal fatty changes and centrilobular hypertrophy of hepatocytes. A proposed mechanism for the toxicity of organic peroxides involves damage via formation of ROS, which is mediated by cytochrome P450. This then leads to lipid peroxidation of the membranes of the hepatocytes, alkylation of cellular macromolecules (reduced glutathione, altered calcium homeostasis.
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Prentice Hall: 2003. 314-20. This directed addition of a proton results in the more thermodynamically stable carbocation intermediate, as determined by degrees of substitution; more highly substituted carbocations are stabilized by the electron-pushing inductive effect of the surrounding carbon molecules. Kharasch, in his seminal 1933 paper entitled "The Addition of Hydrogen Bromide to Allyl Bromide", proposed that the anti-Markovnikov addition of HBr to allyl bromide to yield 1,3-dibromopropane was due to the presence of peroxides. He termed this the "peroxide effect", which he proposed proceeds through a free radical chain reaction addition.
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The largest issue in integrating AM techniques into medical device manufacturing is biocompatibility. These issues arise from the stability of 3D printed polymers in the body and the difficulty of sterilizing regions between printed layers. In addition to the use of primary cleaners and solvents to remove surface impurities, which are commonly isopropyl alcohol, peroxides, and bleach, secondary solvents must be use in succession to remove the cleaning chemicals applied before them, a problem that increases with the porosity of the material used. Common compatibility AM materials include nylon and tissue material from the host patient.
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A peroxide-based bleach or simply peroxide bleach is any bleach product that is based on the peroxide chemical group, namely two oxygen atoms connected by a single bond, (–O–O–). This bond is fairly weak and is often broken in chemical reactions of peroxides, giving rise to very reactive oxygen species, which are the active agents of the bleach. Peroxide-based bleaches became common household products in the late 20th century, being the base of many laundry detergent formulations. Most of these products are adducts of hydrogen peroxide ( or ), that is, solids that contain trapped in a crystal structure together with another material like sodium carbonate or urea.
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Thus, there is considerable evidence that uranyl peroxides such as studtite and metastudtite will be important alteration phases of nuclear waste, possibly at the expense of other minerals, such as uranyl oxides and silicates, which have been more thoroughly studied and are better understood. The formation of these minerals may impact the long-term performance of deep geological repository sites such as Yucca Mountain nuclear waste repository. Due to insufficient information about these minerals it is unknown if they will make radioactive wastes more or less stable, but the presence of studtite and metastudtite provides a pathway for mobilizing insoluble U(IV) from the corroding fuel surface into soluble uranyl species.
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The antioxidant enzyme glutathione peroxidase 4 (GPx4) belongs to the family of glutathione peroxidases, which consists of 8 known mammalian isoenzymes (GPx1-8). Gpx4 catalyzes the reduction of hydrogen peroxide, organic hydroperoxides, and lipid peroxides at the expense of reduced glutathione and functions in the protection of cells against oxidative stress. The oxidized form of glutathione (glutathione disulfide), which is generated during the reduction of hydroperoxides by GPx4, is recycled by glutathione reductase and NADPH/H+. GPx4 differs from the other GPx family members in terms of its monomeric structure, a less restricted dependence on glutathione as reducing substrate, and the ability to reduce lipid-hydroperoxides inside biological membranes.
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Single-use plastic products after their service life often end up in urban areas and in the environment. Most likely, plastic incorrectly disposed of finds its way to lakes, rivers and finally oceans, consisting of danger for marine and terrestrial flora and fauna. The tendency of the plastic to be subjected to photo-oxidation can be positively used and enhanced thanks to the addition of a catalyst. In fact, the plastic with the addition of a catalyst is subject to a fast and aggressive photo- oxidation that degrades the macro and microparticles in fewer harmful sub- products such as low molecular weight compounds (hydroperoxides, peroxides, and carbonyl saturated and unsaturated group).
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Organoperoxides can be reduced to alcohols with lithium aluminium hydride, as described in this idealized equation: :4 ROOH + LiAlH4 → LiAlO2 \+ 2 H2O + 4 ROH The phosphite esters and tertiary phosphines also effect reduction: :ROOH + PR3 → OPR3 \+ ROH Cleavage to ketones and alcohols in the base catalyzed Kornblum–DeLaMare rearrangement Some peroxides are drugs, whose action is based on the formation of radicals at desired locations in the organism. For example, artemisinin and its derivatives, such as such artesunate, possess the most rapid action of all current drugs against falciparum malaria. Artesunate is also efficient in reducing egg production in Schistosoma haematobium infection. Iodine-starch test.
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Prior to the commercialization of the Monsanto process, most acetic acid was produced by oxidation of acetaldehyde. This remains the second-most-important manufacturing method, although it is usually not competitive with the carbonylation of methanol. The acetaldehyde can be produced by hydration of acetylene. This was the dominant technology in the early 1900s. Light naphtha components are readily oxidized by oxygen or even air to give peroxides, which decompose to produce acetic acid according to the chemical equation, illustrated with butane: : 2 C4H10 \+ 5 O2 → 4 CH3CO2H + 2 H2O Such oxidations require metal catalyst, such as the naphthenate salts of manganese, cobalt, and chromium.
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It is prepared by the reaction of hydrogen peroxide and lithium hydroxide. This reaction initially produces lithium hydroperoxide:E. Dönges "Lithium and Sodium Peroxides" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 979. :LiOH + H2O2 → LiOOH + 2 H2O This lithium hydroperoxide has also been described as lithium peroxide monoperoxohydrate trihydrate (Li2O2·H2O2·3H2O). Dehydration of this material gives the anhydrous peroxide salt: :2 LiOOH → Li2O2 \+ H2O2 \+ 2 H2O Li2O2 decomposes at about 450 °C to give lithium oxide: :2 Li2O2 → 2 Li2O + O2 The structure of solid Li2O2 has been determined by X-ray crystallography and density functional theory.
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GPX is most known for its role to protect cells and tissues against oxidative damage by catalyzing the reduction of hydroperoxides using GSH as a reducing substrate and blocking the radical reaction caused by lipid peroxides. By protecting against this oxidative damage, GPX essentially prevents against degenerative diseases such as atherosclerosis, myocardial ischemia, heart failure, diabetes, pulmonary fibrosis, neurodegenerative disorders, and Alzheimer’s disease. However, because of GPX’s poor stability and paucity, it cannot be used in clinical studies and other methods must be considered. The newfound seleno-hGSTZ1–1 (or the engineered GSTZ1 enzyme) has a high GPX activity and a very similar reaction mechanism to that of GPX.
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TBPB is a clear light yellow liquid, which is little soluble in water but well in many organic solvents such as ethanol or phthalate.United Initiators, Technisches Datenblatt, TBPB As peroxo compound, TBPB contains about 8.16 wt% of active oxygen and has a self accelerating decomposition temperature (SADT) of about 60 °C. The SADT is the lowest temperature at which self-accelerating decomposition in the transport packaging can occur within a week, and which should not be exceeded while storage or transportation.Organic Peroxide Producers Safety Division, SAFETY AND HANDLING OF ORGANIC PEROXIDES The Society of the Plastics Industry, 2012 edition TBPB should therefore be stored between minimum 10 °C (below solidification) and maximum 50 °C.
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Salvaged container at Terschelling beach On 1 January 2019 342 containers went overboard on the North Sea. 297 containers lost north of the Dutch island Ameland, the remaining containers some hours later north of the German island Borkum.Onderzoeksraad voor Veiligheid onderzoekt overboord slaan containers Nos News, 10 January 2019 19 of the containers and their contents – including organic peroxides, children's toys, shoes, bags, cushions, chairs, televisions, and plastic packaging – washed ashore on the Dutch islands of Vlieland, Terschelling, Ameland and Schiermonnikoog and German island Borkum in the Wadden Sea, a protected UNESCO biosphere reserve.Rijkswaterstaat: 222 containers gelokaliseerd (update) RTV Noord, 6 January 2019 The Dutch Safety Board started an investigation into the case.
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Lev Vladimirovich Pisarzhevsky was born on 13 February 1874 Kishinev in the Bessarabia Governorate of the Russian Empire (now Chişinău, Republic of Moldova). His mother relocated the family to Odessa following his father's death, where Lev Pisarzhevsky worked to support the family and studied at a school of classical education. He graduated from Novorossiysky University (now Odessa National University) in 1896 and proceeded to work on inorganic peroxides with his university instructor P. G. Melikov. He spent the period from 1900 to 1903 abroad, where he worked in Germany with Wilhelm Ostwald in 1900-1902 and also became acquainted with such leading Western European contributors to physical chemistry as Jacobus Henricus van 't Hoff, Svante Arrhenius, and Walther Nernst.
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In addition to the Low Temperature Warehouses, power was also cut off to other structures, the water supply and fire suppression pumps. Additionally some of the backup electrical generators were also compromised by floodwaters, along with the piping for emergency liquid nitrogen tank that was on hand should the mechanical (electrically powered) refrigeration fail. Workers were able to restore this temporarily, however the piping was later submerged again by floodwaters. By the end of the night, only one Low Temperature Warehouse was still operational, with the organic peroxides from the other six warehouses now stored in six refrigerated trailers, now being stored in the 'laydown area' one of the highest points in the facility.
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The ride-out crew discovered one of the refrigerated trailers that could not be moved from the warehouses had started to lean, and likely going to fail. Additionally, the Arkema corporate crisis team suspected there would be at least one fire caused by decomposition of the organic peroxides, and decided to have the ride-out crew evacuate the facility. After a final inspection by boat, the ride-out crew was evacuated by Harris County emergency responders by boat around 12:00pm CDT. At some point during the day, the secondary containment dikes around the wastewater tanks were overcome by floodwaters, and two tanks released approximately of organic materials mixed with floodwaters and escaped the facility.
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Many scientists believe that the data were due to inorganic chemical reactions of the soil; however, this view may be changing due to a variety of discoveries and studies since Viking, including, the discovery of near-surface ice near the Viking landing zone, the possibility of perchlorate destruction of organic matter, and the reanalysis of GCMS data by scientists in 2018. Some scientists still believe the results were due to living reactions. The formal declaration at the time of the mission was that the discovery of organic chemicals was inconclusive. Mars has almost no ozone layer, unlike the Earth, so UV light sterilizes the surface and produces highly reactive chemicals such as peroxides that would oxidize any organic chemicals.
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He was also involved in research on demyelination of peripheral nerve sheaths and also showed that black osmium staining light microscopy and its electron density for electron microscopy, appears first in carbohydrates before it stains unsaturated lipids. He also demonstrated the presence of a carbohydrate-containing moiety in myelin (later shown by others to be different proteoglycans) and its importance in myelin breakdown. His research was focused on the oxidation of lipids, the formation of lipid peroxides, their polymerization, and the pathogenesis and nature of lipid pigments. In 1959, Wolman was appointed head of the Department of Pathology of the Tel Hashomer Government Hospital (later renamed as the Chaim Sheba Medical Center).
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Bioventing is a process that increases the oxygen or air flow into the unsaturated zone of the soil which increases the rate of natural in situ degradation of the targeted hydrocarbon contaminant. Approaches for oxygen addition below the water table include recirculating aerated water through the treatment zone, addition of pure oxygen or peroxides, and air sparging. Recirculation systems typically consist of a combination of injection wells or galleries and one or more recovery wells where the extracted groundwater is treated, oxygenated, amended with nutrients and reinjected. However, the amount of oxygen that can be provided by this method is limited by the low solubility of oxygen in water (8 to 10 mg/L for water in equilibrium with air at typical temperatures).
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Mutations in the subunits of complex I can cause mitochondrial diseases, including Leigh syndrome. Point mutations in various complex I subunits derived from mitochondrial DNA (mtDNA) can also result in Leber's Hereditary Optic Neuropathy. There is some evidence that complex I defects may play a role in the etiology of Parkinson's disease, perhaps because of reactive oxygen species (complex I can, like complex III, leak electrons to oxygen, forming highly toxic superoxide). Although the exact etiology of Parkinson’s disease is unclear, it is likely that mitochondrial dysfunction, along with proteasome inhibition and environmental toxins, may play a large role. In fact, the inhibition of complex I has been shown to cause the production of peroxides and a decrease in proteasome activity, which may lead to Parkinson’s disease.
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This theory is further supported by a cross-sectional study which found elevated mean serum lipid peroxides (LPO) in the As exposed individuals which correlated with blood levels of inorganic arsenic and methylated metabolites and inversely correlated with nonprotein sulfhydryl (NPSH) levels in whole blood. Another study found an association of As levels in whole blood with the level of reactive oxidants in plasma and an inverse relationship with plasma antioxidants. A finding of the latter study indicates that methylation might in fact be a detoxification pathway with regard to oxidative stress: the results showed that the lower the As methylation capacity was, the lower the level of plasma antioxidant capacity. As reviewed by Kitchin (2001), the oxidative stress theory provides an explanation for the preferred tumor sites connected with arsenic exposure.
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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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Readily combustible solids are powdered, granular, or pasty substances which are dangerous if they can be easily ignited by brief contact with an ignition source, such as a burning match, and if the flame spreads rapidly. it is further divided into • flammable solids, • polymerizing substances # self-reactive substances, are thermally unstable solids liable to undergo a strongly exothermic thermal decomposition even without participation of oxygen (air), other than materials classified as explosive, organic peroxides or as oxidizing. # pyrophoric substance more colloquially described as spontaneously combusting substances are those solids or liquids that even in small quantities are liable to ignite within five minutes after coming into contact with air. Substances and mixtures of this hazard class are assigned to a single hazard category on the basis of the outcome of the UN Test N.2.
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In a 2007 analysis it was shown that, when modern statistical methods for correcting for the effects of body size and phylogeny are employed, metabolic rate does not correlate with longevity in mammals or birds. (For a critique of the Rate of Living Hypothesis see Living fast, dying when?) With respect to specific types of chemical damage caused by metabolism, it is suggested that damage to long- lived biopolymers, such as structural proteins or DNA, caused by ubiquitous chemical agents in the body such as oxygen and sugars, are in part responsible for aging. The damage can include breakage of biopolymer chains, cross-linking of biopolymers, or chemical attachment of unnatural substituents (haptens) to biopolymers. Under normal aerobic conditions, approximately 4% of the oxygen metabolized by mitochondria is converted to superoxide ion, which can subsequently be converted to hydrogen peroxide, hydroxyl radical and eventually other reactive species including other peroxides and singlet oxygen, which can, in turn, generate free radicals capable of damaging structural proteins and DNA.
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