Pulse radiolysis of methyl acetate in aqueous solutions

Abstract

The absorption spectrum and decay kinetics of the products of the reaction of the OH radical with methyl acetate in aqueous solutions have been studied using the pulse-radiolysis technique. The OH radical preferentially abstracts an H atom from the alkoxyl group of the ester. The organic radicals react with oxygen to form peroxy radicals and the rate constants k R+ O 2 = (1.35±0.15) × 10 10 and (1.8±0.2) × 10 9 dm 3 mol -1 s -1 were obtained for CH 3CO 2CH 2· and ·CH 2CO 2 CH 3 radicals, respectively. The CH 3CO 2CH 2O 2· radicals decay by a second-order process, k = (2.9±0.3) × 10 9 dm 3 mol -1 s -1, and do not produce O 2 - radicals. Radical ions formed by addition of electrons to the carbonyl group of methyl acetate decompose by a first-order reaction, k= 5.5 × 10 5 s -1, to produce acetyl radicals.