Peroxide organic

Organic peroxides can occur in small amounts in some types of polymers such as PS as a result of the fact that a peroxide has been used as a polymerisation catalyst in polymer manufacture. Also, stable organic peroxides such as dicumyl peroxide have been used as synergists, in conjunction with bromine and or phosphorus-containing additives, to impart fire resistance to cellular expanded PS and other types of plastics. 

Peroxyacetic and peroxybenzoic acids gave reduction waves at 0.00 voltage in the presence of ethylcellulose and methylene blue, but they did not demonstrate a linear relationship between diffusion current and concentration. The acids evidently reacted slowly with the methanol in the solvent, as a continuous decrease in diffusion current was observed with increased time of contact. Peroxyacetic acid showed an additional wave at a half-wave potential of -1.41 V, probably because of the presence of acetic acid, whose half-wave potential was observed to be 1.44 V. Bis(l-hydroxyheptyl)peroxide gave two reduction waves at 0.00 and -1.20 V. A linear relationship existed between the concentration (1 x 10 to 1.3 x lO M) and diffusion current at half-wave potential of -1.20 V, but not at 0.00 voltage. 

In the second group in Table 2.15, two reduction waves were obtained for each of the three peroxides, the first at -0.60 to -0.70 V, the second at -1.0 to -1.26 V. Methyl ethyl ketone peroxide in dimethyl phthalate showed three half-wave potentials, one of which (-1.82 V) was attributed to the phthalate ester, the first reduction wave (0.60 V) was observed only when the concentration of peroxide was below 0.01 M, and the relationship between diffusion current and concentration was nonlinear, since the diffusion current showed a maximum at a concentration of 2.1 x 10 M. The second reduction wave (half- 

Compounds Peroxide Structure Peroxide content (%) Half-wave potential, (volts) 

Recommendations defines organic peroxide as organic substances which contain the bivalent -0-0- structure and may be considered derivatives of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. 

Organic peroxides are thermally unstable substances which may undergo exothermic self-accelerating decomposition. The Japanese Fire Services Law has revised its classification to regulate organic peroxides as self-reactive substances. 

Almost all organic peroxides are thermally and photolyticaHy sensitive owing to the facile cleavage of the weak oxygen—oxygen bond, ie, the range of AHis about —84 to —184 kJ/mol (—20 to —44 kcal/mol) (9—11)  

Because many organic peroxides undergo thermolysis to form useful free radicals, they are used commercially as initiators for free-radical reactions. Many organic peroxides also undergo reactions in which free radicals are not involved, eg, heterolyses, hydrolyses, reductions, and rearrangements. Numerous reviews of the chemistry and appHcations of organic peroxides have been pubHshed (11,13—41). 

Organic peroxides can be classified according to peroxide stmcture. There are seven principal classes hydroperoxides dialkyl peroxides a-oxygen substitued alkyl hydroperoxides and dialkyl peroxides primary and secondary ozonides peroxyacids diacyl peroxides (acyl and organosulfonyl peroxides) and alkyl peroxyesters (peroxycarboxylates, peroxysulfonates, and peroxyphosphates). 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

There are two main subclasses ofhydroperoxid.es organic (alkyl) hydroperoxides, ie, ROOH, and organomineral hydroperoxides, ie, Q(OOH), where Q is sihcon (43), germanium, tin, or antimony. The alkyl group in ROOH can be primary, secondary, or tertiary. Except for ethylbenzene hydroperoxide, only alkyl hydroperoxides are commercially important. 

The heading of Class 5.2 covers organic peroxides and formulations of organic peroxides. The substances of Class 5.2 are subdivided as follows  

PI Organic peroxides not requiring temperature control P2 Organic peroxides requiring temperature control 

Any organic peroxide shall be considered for classification in Class 5.2 unless the organic peroxide formulation contains 

Label (flame above a circle) black on yellow background 

TYPE A Organic peroxide that can detonate or deflagrate rapidly as packaged for transport. Transportation of type A organic peroxides is forbidden. 

TYPE B Organic peroxide as packaged for transport, neither detonates nor deflagrates rapidly, but can undergo a thermal explosion. 

TYPE E Organic peroxide which neither detonates nor deflagrates and shows low, or no, effect when heated under confinement. 

TYPE F Organic peroxide which will not detonate in a cavitated state, does not deflagrate, shows only a low, or no, effect if heated when confined, and has low, or no, explosive power. 

The results of polymerizations using these various initiators are shown in Table 6.4. The best results were obtained with FC-8 thus a number of aqueous suspension polymerizations were run under a variety of conditions using FC-8 dissolved and fed to the reaction in several different solvents. The results are shown in Table 6.5. The low yields are probably due to precipitation, premature decomposition in the feed line, or hydrolysis of the FC-8 peroxide prior to 

Example Initiator Yield (%) Inherent viscosity (dl/g in C6F5C1) 

Smokeless powders, solid low explosives, are virtually smokeless in comparison to black powder. They are also less susceptible to damp, store better, are more powerful, and bum at a more easily controlled rate. These benefits come with the disadvantage that they bum hotter and cause greater damage to the barrels of weapons in which they are used extensively as ammunition propellants. The length of a weapon s barrel and other ballistic requirements result in smokeless powder for pistol ammunition being in flakes, which bums quickly, while slower burning balls, cylinders, or tubes are used for rifle ammunition riflepowder). There are three types of smokeless powder  

Single-base propellants, those composed chiefly of nitrocellulose (NC, 9004-70-0) with a nitrogen content above 13%. 

Double-base propellants of NC and nitroglycerine (NG, 55-63-0) although nitrate esters may replace NG. More powerful than single-base propellants, these also generate higher temperatures and more wear on the barrel of the weapon. 

Triple-base propellants of NC, NG, and nitroguanidine (556-88-7). These marry the higher power of double-bases with the cooling affect of nitroguanidine to minimize barrel wear. 

Smokeless powders contain stabilizers like diphenylamine to remove nitrogen oxides and other products of the decomposition of nitro compounds, and other additives such as potassium acid salts (to smother the muzzle flash) and camphor and dimethyl phthalate which are manufacturing processing aids. 

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SOME AROMATIC PEROXIDES AND PER-ACIDS Organic peroxides may be prepared —... 

To determine the exact peroxide content of benzoyl peroxide (and of other organic peroxides) the following procedure may be employed. Place about 0 05 g. of the sample of peroxide in a glass-stoppered conical flask add 5-10 ml. of acetic anhydride (A.R. or other pure grade) and 1 g. of powdered sodium iodide. Swirl the mixture to dissolve the sodium iodide and allow the solution to stand for 5-20 minutes. Add 50-75 ml. of water, shake the mixture vigorously for about 30 seconds, and titrate the liberated iodine with standard sodium thiosulphate solution using starch as indicator. 

Organic peroxides are highly explosive, hence it is best to carry out the ozonisation in a solvent which dissolves both the original compound and the ozonide. 

In addition to CuCfi, some other compounds such as Cu(OAc)2, Cu(N03)2-FeCl.i, dichromate, HNO3, potassium peroxodisulfate, and Mn02 are used as oxidants of Pd(0). Also heteropoly acid salts comtaining P, Mo, V, Si, and Ge are used with PdS04 as the redox system[2]. Organic oxidants such as benzo-quinone (BQ), hydrogen peroxide and some organic peroxides are used for oxidation. Alkyl nitrites are unique oxidants which are used in some industrial... 

Organic peroxides are used extensively for the curing of unsaturated polyester resins and the polymerization of monomers having vinyl unsaturation. The —O—O— bond is split into free radicals which can initiate polymerization or cross-linking of various monomers or polymers. 

PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) Acetyl-b-methylcholine chloride [62-51-1]... 

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