Reactions of the primary radical cations of carboxylic acids as studied by ESR in freonic matrices

Abstract

Radical products of radiolysis of frozen solutions of propionic and butyric acids were studied in the matrices of Freon-11, Freon-113, and Freon-113a at 77 K. It was shown that the primary radical cations generated by radiation were not trapped in the freonic matrices (in contrast with the corresponding freonic solutions of acetic acid). The radical cations of propionic and butyric acids decay in concurrent processes of rearrangements yielding terminal-type and ylide-type distonic radical cations and intramolecular proton transfer in the dimeric radical cations resulting in acyloxy radicals. The latter species undergo decarboxylation to yield ethyl and propyl radicals for propionic and butyric acids, respectively. According to mass-spectrometric data, the terminal-type distonic radical cations undergo the McLafferty rearrangement.