Reaction of perfluoroethyl radicals with cycloalkanes

Abstract

The reactions of C₂F₅ radicals with C₄ to C₇ cycloalkanes have been studied using perfluoroethyl iodide as the source of free radicals. The Arrhenius parameters obtained for the reaction C₂F₅+ c-RH→C₂F₅H + c-R were (c-R = cycloalkyl): [graphic omitted] The Arrhenius parameters are compared with those for corresponding CF₃ radical reactions. From the activation energies, values for the c-R—H bond dissociation energies are derived using the Evans–Polanyi method. Bond strengths for methylene groups in C₅, C₆ and C₇ cycloalkanes are all close to that for the Prⁱ—H bond dissociation energy in propane.