Anisoyl peroxide

By a procedure similar to that described for />-nitrobenzoyl peroxide, the following peroxides have been prepared w-nitro-benzoyl peroxide (m.p. 136-137°) in 90 per cent yield anisoyl peroxide (m.p. 126-127°) in 86-89 per cent yields -bromoben-zoyl peroxide (m.p. 144°) in 73 per cent yield and 3,4,5-tribromo-benzoyl peroxide (m.p. 186°) in 40 per cent yield.1 The procedure is not satisfactory for preparation of acetylsalicylyl peroxide, which is more conveniently prepared by action of hydrogen peroxide upon an acetone solution of the acid chloride. 

Nitrobenzoyl peroxide,2 as well as w-nitrobenzoyl peroxide2 and anisoyl peroxide,3 have been prepared in about 50 per cent yields from the acid chlorides and an acetone solution of hydrogen peroxide, in the presence of a basic substance such as pyridine, sodium acetate, or sodium hydroxide. w-Nitrobenzoyl peroxide has also been prepared by nitration of benzoyl peroxide with cold... 

Since the analogous peroxides usually decompose by a free radical mechanism, it is noteworthy that this hydroxamic acid is not sensitive to the action of free radicals from anisoyl peroxide. A radical chain mechanism like that shown below can therefore be ruled out for this compound. 

The use of labelled initiators to obtain accurate information concerning the relative reactivities of radical scavengers towards reference radicals, has been reviewed (4). Product analysis, by isotope dilution analysis, has been used in the examinations of the decompositions of certain initiators in the absence of monomers. It is possible to work with very dilute solutions and small extents of decomposition so that the conditions are similar to those prevailing when the substances are used as initiators of polymerizations. The decompositions of dibenzoyl (12) and di-anisoyl peroxides (13), for example, have been followed by determinations of the carbon dioxide evolved. 

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