Heat of formation of the CF2Cl· radical

Abstract

Arrhenius parameters for the reactions : CF₃·+ CF₂HCl → CF₃H + CF₂Cl·(1), CF₂Cl·+ CF₃H → CF₂HCl + CF₃. (2), are: k₁= 2.0 ± 0.2 × 10¹¹ exp(–10 770 ± 700/RT) cm³ mol^–1 s^–1, k₂= 8.0 ± 0.2 × 10¹¹ exp(–13 680 ± 400 /RT) cm³ mol^–1 s^–1. The difference in the energies of activation, combined with known thermochemical data gives a value for the heat of formation of the CF₂Cl· radical of –64.3 kcal and a value for D(CF₂Cl—H) of 103.8 kcal. Combination of this value with the measured appearance potential of (CF₂Cl⁺) from CF₂Cl₂ gives a value for the ionization potential of the CF₂Cl· radical of 9.1eV. Bond-dissociation energies in several molecules containing the CF₂Cl· radicals have been determined from the appropriate appearance potentials of (CF₂Cl⁺).