Diacyl peroxide amine

The diacyl peroxide-amine system, especially BPO-DMT or BPO-DMA, has been used and studied for a long time but still no sound initiation mechanism was proposed. Some controversy existed in the first step, i.e., whether there is formation of a charge-transfer complex of a rate-controlling step of nucleophilic displacement as Walling 1] suggested ... 

Diacyl peroxide] = [amine] = 1.0 x 10 mol/L,45 C HDMA p-hydroxymethyl-A/,A/-dimethylaniline NDMA p-nitro-A/,A/-dimethylani-line DMAB p-dimethylaminobenzaldehyde. 

Diacyl peroxides Amines (e.g. iVdV-dimethylaniline), certain sugars... 

Aromatic diacyl peroxides such as dibenzoyl peroxide (BPO) [94-36-0] may be used with promoters to lower the usehil decomposition temperatures of the peroxides, although usually with some sacrifice to radical generation efficiency. The most widely used promoter is dimethylaniline (DMA). The BPO—DMA combination is used for hardening (curing) of unsaturated polyester resin compositions, eg, body putty in auto repair kits. Here, the aromatic amine promoter attacks the BPO to initially form W-benzoyloxydimethylanilinium benzoate (ion pair) which subsequentiy decomposes at room temperature to form a benzoate ion, a dimethylaniline radical cation, and a benzoyloxy radical that, in turn, initiates the curing reaction (33) ... 

Amines also react with diacyl peroxides by nucleophilic displacement on the oxygen—oxygen bond forming an ion pair iatermediate (187) ... 

The fate of the ion pair iatermediate depends on the stmcture of the amine and the reaction conditions. Certain tertiary amines, eg, dimethylaruline (DMA), react with specific diacyl peroxides such as diben2oyl peroxide (BPO) to generate free radicals at ca 20°C. Some reactions, eg, DMA—BPO, are explosive when neat reactants are mixed. Primary and secondary amines do not yield free radicals. 

Qiu et al. [11] reported that the aromatic tertiary amine with an electron-rich group on the N atom would favor nucleophilic displacement and thus increase the rate of decomposition of diacyl peroxide with the result of increasing the rate of polymerization (Table 1). They also pointed out that in the MMA polymerization using organic peroxide initiator alone the order of the rate of polymerization Rp is as follows ... 

Nitro- and nitroso-compounds,170171 amines, and thiols induce the decomposition of diacyl peroxides in what may be written as an overall redox reaction. Certain monomers have been reported to cause induced decomposition of BPO. These include AN,172 A -vinylcarbazole,17,177 Ar-vinylimidazole178 and NVP.177... 

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... 

Most of the isolated diacyl (including sulfonyl) peroxides are solids with relatively low decomposition temperatures, and are explosive, sensitive to shock, heat or friction. Several, particularly the lower members, will detonate on the slightest disturbance. Autocatalytic (self-accelerating) decomposition, which is promoted by tertiary amines, is involved [1]. Solvents suitable for preparation of safe solutions of diacetyl, dipropionyl, diisobutyryl and di-2-phenylpropionyl peroxides are disclosed [2], The class is reviewed, including hazards and safety measures [3], Cyclic diacyl peroxides are more stable, but scarcely to be trusted. Individually indexed compounds are ... 

Hydrogen peroxide Peroxodisulfates Diacyl peroxides Hydroperoxides Peracid ester Ag+,Fe2+,Co +,Tp+ Hydrogen sulfites, sulfites, thiosulfates, mercaptans, sulfinic acids Amines (e.g. NdV-dimethylaniline), certain sugars Benzoin/Fe Hydrogen sulfite/Fe ... 

Active carbonyl compounds interfere by forming acetals or ketals by reaction with methanol. The interference can be avoided by adding hydrogen cyanide to form cyanohydrins that do not interfere. Other interfering substances include mercaptans and certain amines, which react with iodine, and various oxidizing substances such as peroxy acids, diacyl peroxides, and quinones, which react with iodide to produce iodine. 

The most extensive studies of oxidation by diacyl peroxides have been carried out on secondary amines, and because many of the conclusions are applicable to other types of amines, these reactions will be considered first. 

Primary amines react less readily with diacyl peroxides than either secondary or tertiary amines. The reaction results in a complex mixture of products . From aniline and benzoyl peroxide, for instance, benzoic acid, benzanilide, azoxybenzene and a little o-hydroxybenzanilide can be isolated . Their formation can be rationalised from an initial attack by benzoyl peroxide to give both 0-benzoylphenylhydroxylamine (34) plus benzoic acid and benzanilide (35) plus perbenzoic acid (Scheme 32). Subsequent hydrolysis. 

The reactions of tertiary phosphines are frequently driven by formation of the thermo-dynamically-stable phosphoryl (P=0) bond. Deoxygenation reactions are common in phosphine chemistry many oxygen-containing compounds, for instance diacyl peroxides, peresters, alkyl hydroperoxides, ozonides, amine oxides and sulphoxides, react with phosphines ... 

The initiator usually is created in a redox reaction that follows a free radical pathway. Common reactions involve the reduction of an organic peroxide by some reducing agent such as an amine or an ion capable of undergoing a one-electron transfer reaction. One example of an efficient free radical initiator generating reaction is the reduction of diacyl peroxides such as benzoyl peroxide (BPO) by tertiary aromatic amines such as N,N-dimethyl aniline (DMA). 

Uses Intermediate in fragrances, flavors, pharmaceuticals, cosmetics, amines, metal soaps, detergents, diacyl peroxides, esters Properties Lt, liq, typ, odor acid no, 476-484 iodine no, 0-1 sapon. no. 476-484 0-0,5% water... 

The products from diacyl and benzoyl peroxide oxidation depend very much on the structure of the tertiary amine The initial... 

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