Ab initio and RRKM studies of the unimolecular reactions of CH2XCHFO (X = H, F) radicals

Abstract

The unimolecular reaction mechanism of the CH₂XCHFO (X = H, F) radicals was studied using the ab initio G2(MP2, SVP) theory. Three kinds of reaction pathways, namely bond scission, three-center elimination of HF and isomerization, were examined. Both the energy-specific rate constant [k(E)] and the thermal rate constant [k(T, P)] were evaluated using the RRKM theory and the ab initio data. These theoretical calculations support the proposal that the C–C bond scissions dominate the decomposition of CH₂XCHFO (X = H, F). The major products of the unimolecular reactions should be CH₂X and CHFO. Furthermore, it is concluded that the lifetimes of CH₃CHFO and CH₂FCHFO are both very short in the atmosphere.