Diacetyl peroxides

Diluents such as dimethyl phthalate, dibutyl phthalate, tricresyl phosphate, silicone fluid, benzene, toluene, xylene, cyclohexane, dichloroethane, mineral spirit, water and fire-retardant pastes, and so on, are used which greatly lower the shock and heat sensitivity of peroxides. Care should be taken to maintain the storage temperature within the recommended temperatme range. Too much coohng can result in crystallizations of peroxides from their diluent solvents and can cause danger. 

Instrumental methods for analysis depend on the natme of peroxide. Gas chromatography is applicable where peroxides are thermally stable. It may also be applied as a pyrolytic decomposition technique in which the decomposition products are separated and quantified (Swem 1986). Liquid and column chromatography, thin-layer chromatography, and paper chromatography have been used for analyses of peroxides. 

Peroxides can be reduced by excess iodide ion in acetic acid or isopropanol solvents, and the liberated iodine may be titrated with standard thiosulfate solution. Iodide ion, titanium(IV), ferrous ion, and N,N-dimethyl-p-phenylenediamine are some of the reducing reagents used for colorimetric analyses for trace peroxides. 

Peroxides that are reduced irreversibly at the mercury electrode can be analyzed by polarography. IR, UV, NMR, and GC/MS are useful in structure characterization. IR absorption bands at 800-900 cm and in the region of carbonyl group are characteristics of diacyl peroxides, peroxydicarbonates, and peroxyesters. 

DOT Label Forbidden for solid and solutions with strength over 25% DOT UN 2084 for solutions less than 25% 

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The extent of decarboxylation primarily depends on temperature, pressure, and the stabihty of the incipient R- radical. The more stable the R- radical, the faster and more extensive the decarboxylation. With many diacyl peroxides, decarboxylation and oxygen—oxygen bond scission occur simultaneously in the transition state. Acyloxy radicals are known to form initially only from diacetyl peroxide and from dibenzoyl peroxides (because of the relative instabihties of the corresponding methyl and phenyl radicals formed upon decarboxylation). Diacyl peroxides derived from non-a-branched carboxyhc acids, eg, dilauroyl peroxide, may also initially form acyloxy radical pairs however, these acyloxy radicals decarboxylate very rapidly and the initiating radicals are expected to be alkyl radicals. Diacyl peroxides are also susceptible to induced decompositions ... 

This ladical-geneiating reaction has been used in synthetic apphcations, eg, aioyloxylation of olefins and aromatics, oxidation of alcohols to aldehydes, etc (52,187). Only alkyl radicals, R-, are produced from aliphatic diacyl peroxides, since decarboxylation occurs during or very shortiy after oxygen—oxygen bond scission in the transition state (187,188,199). For example, diacetyl peroxide is well known as a source of methyl radicals (206). 

Chemical Designations — Synonyms Diacetyl Peroxide Solution Chemical Formula CH3CO(Oi)OCCH3 in dimethyl phthalate. 

Arsine (also c.illed Arsenic yclride) 7784-42-1 100 Diacetyl Peroxide (concentration greater than 10% ) 1 III-. - ... 

One of the most commonly encountered aliphatic diacyl peroxides (36, R=alkyl) is LPO. Lower diacyl peroxides (e.g. diacetyl peroxide) cannot be... 

The chlorination of methyl chloroformate in sunlight was first reported by Hentschel, but without a detailed description of either the procedure or the results. The first step of the present procedure for the preparation of trichloromethyl chloroformate utilizes an ultraviolet light source and affords a simple and reproducible way to obtain this reagent. Although trichloromethyl chloroformate may also be synthesized by photochemical chlorination of methyl formate,the volatility of methyl formate causes losses during the reaction and increases the hazard of forming an explosive mixture of its vapor and chlorine gas. The preparation of trichloromethyl chloroformate by chlorination of methyl chloroformate in the dark with diacetyl peroxide as initiator has been reported. However, the procedure consists of several steps, and the overall yield is rather low. 

Organic peroxides have a low toxicity. The diacetyl peroxides are sensitive to heat, friction, and shock and may detonate upon the slightest mechanical disturbance. Benzoyl peroxide dust may explode easily by friction. Anyone designing... 

Following a published procedure [1], octene was treated with a solution of perox-yacetic acid in acetic acid for 8 h to form the epoxide, but the reaction mixture was then allowed to stand uncooled overnight. Next morning, when a 3pl sample was injected into a heated GLC injection port, the syringe shattered. This was attributed to formation of diacetyl peroxide during the overnight standing, and its subsequent explosion in the heated port [2],... 

Application of fluorine to aqueous sodium acetate solution causes an explosion, involving formation of diacetyl peroxide. 

During preparation of peracetic acid solutions for textile bleaching operations, the reaction mixture must be kept acid. Under alkaline conditions, highly explosive diacetyl peroxide separates from solution [1], An excess of the anhydride has the same effect [2],... 

Interaction with excess ketene rapidly forms explosive diacetyl peroxide. 

The crude products of ozonolysis at — 30°C of the chloroalkene tended to decompose explosively on warming to ambient temperature, particularly in absence of solvents. The products included the individually explosive compounds acetyl 1,1,-dichloroethyl peroxide, 3,6-dichloro-3,6-dimethyl-2,3,5,6-tetraoxane and diacetyl peroxide [1], Ozonolysis in ethyl formate saturated with hydrogen chloride gives a high yield of 1,1-dichloroethyl hydroperoxide as a further unstable intermediate product [2],... 

Generated from diacetyl peroxide, methyl radicals attack 2-methylfuran at position 5 preferentially if both 2- and 5-positions are occupied as in 2,5-dimethylfuran there is still little or no attack at the 3(4)-position. If there is a choice of 2(5)-positions, as in 3-methylfuran, then that adjacent to the methyl substituent is selected.249 These orientation rules are very like those for electrophilic substitution, but are predicted for radical attack by calculations of superdelocalizability (Sr) by the simple HMO method. Radical bromination by IV-bromsuccinimide follows theory less closely, presumably because it does not occur through a pure radical-chain mechanism.249... 

B. M. Tolbert and M. Calvin Decomposition of Diacetyl Peroxide in Acetic Acid. (UCRL) 573 (1949). 

The Rate Constants of the Thermal Decay of Diacetyl Peroxide in Different Solvents ... 

The back recombination of the pair of acetoxyl radicals with the formation of parent diacetyl peroxide was observed in special experiments on the decomposition of acetyl peroxide labelled by the lsO isotope on the carbonyl group [78,79]. The reaction of acetyl peroxide with NaOCH3 produces methyl acetate and all lsO isotopes are contained in the carbonyl... 

The higher the viscosity of the solvent, the higher the amount of the parent molecules formed due to the geminate recombination of radicals. The observed rate constant of decomposition of the initiator decreases with an increase in viscosity [3,90], This was observed in the decomposition of peresters and diacetyl peroxide in various solutions. Subsequently, the fraction fT of the radical pairs recombining to the parent molecule increases with an increase in the viscosity ... 

Diacetoxyscirpenol (DAS) immunoassay, 14 144-147 Diacetyl, 23 483 Diacetyl control, 10 293 Diacetyl peroxide, 1 148 Diacetyl rest, in beer making, 3 584 Diacrylamide, 1 293 Diacylglycerols, 10 802 Diacyl hydrazines, 13 599 Diacyl peroxides, 14 281 18 467 decomposition of, 18 473 as free-radical initiators, 14 282-284 hydrolysis and perhydrolysis of, 18 466, 473 preparation of, 18 476 properties of, 18 468-469t reaction with amines, 18 474 reduction of, 18 474 symmetrical or unsymmetrical, 18 477... 

One of the first synthetic applications of organoboranes in radical chemistry is the conjugate addition to enones (Scheme 23, Eq. 23a) and enals reported by Brown [58-61]. Addition to -substituted enones and enals are not spontaneous and initiation with the oxygen [62], diacetyl peroxide [63], or under irradiation [63] is necessary (Eq. 23b). A serious drawback of this strategy is that only one of the three alkyl groups is efficiently transferred, so the method is restricted to trialkylboranes derived from the hydroboration of easily available and cheap alkenes. To overcome this limitation B-alkylboracyclanes have been used but this approach was not successful for the generation of tertiary alkyl radicals [64,65]. 

Phosphorus trichloride combines with olefins in the presence of diacetyl peroxide 7... 

Bis(fluoroformyl) peroxide, 0625 Bis-3-(2-furyl)acryloyl peroxide, 3640 Bis(trichloroacetyl) peroxide, 1361 Bis(trifluoroacetyl) peroxide, 1367 Diacetyl peroxide, 1537 Dibenzenesulfonyl peroxide, 3499 Dibenzoyl peroxide, 3639 Di-3-camphoroyl peroxide, 3807 Dicrotonoyl peroxide, 2986 Dicyclohexylcarbonyl peroxide, 3667 Didodecanoyl peroxide, 3857 Di-2-furoyl peroxide, 3245 Dihexanoyl peroxide, 3554 Diisobutyryl peroxide, 3032 Diisopropyl peroxydicarbonate, 3034 Dimethanesulfonyl peroxide, 0931 Di-2-methylbutyryl peroxide, 3354 Di-l-naphthoyl peroxide, 3831 3,6-Dioxo-l,2-dioxane, 1445 Dipropionyl peroxide, 2442 Dipropyl peroxydicarbonate, 3035 Di-4-toluenesulfonyl peroxide, 3656 Peroxodisulfuryl difluoride, 4328 Phthaloyl peroxide, 2900 Potassium benzenesulfonylperoxosulfate, 2257 Potassium O-O-benzoylmonoperoxosulfate, 2684 (9-TriIIuoroacctyl-.S -lluorofonny 1 thioperoxide, 1050 See PEROXIDES, PEROXYCARBONATE ESTERS... 

Reaction with acetyl chloride yields diacetyl peroxide. Similar diacyl peroxides are formed from other acyl chlorides ... 

Table II. Rates of Scrambling of Carbonyl Label in Diacetyl Peroxide at 80°C.

Diacetyl Peroxide Highly explosive to be handled only with extraordinary caution L.P. Kuhn, C EN 26, 3197 (1948)... 

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