Non-Arrhenius behaviour in the reaction of CF3 radicals with CH3CN and CD3CN

Abstract

Evidence is presented that rate measurements over a wide temperature range, 298–648 K, for the reaction of CF₃ radicals with methyl cyanide show non-Arrhenius behaviour when the photolysis of trifluoromethyl iodide is used as a source of radicals. The results presented here support the fact that the curved Arrhenius plot may be explained in terms of two reaction channels giving the same product, CF₃H. One is the abstraction reaction by the CF₃ radical and the other involves the iodine atom produced in the photolysis of CF₃I. In order to obtain further information on the reaction mechanism the kinetic isotope effect has also been studied.