Isotope effects in reactions of trifluoromethyl radicals with hydrogen chloride and hydrogen sulphide

Abstract

Rate constants, Arrhenius parameters and primary kinetic isotope effects have been measured for the reactions of trifluoromethyl radicals with H₂S, D₂S, HCl and DCl: [graphic omitted] Quotients of A-factors do not differ significantly from unity, but values for (E_D–E_H) are significantly less than the respective zero-point-energy differences ΔE₀ of 1.1 kcal mole^–1. The reactivity of CF₃ radicals towards the two substances is markedly less than that of CH₃ radicals; the differences reside in the higher activation energies and may be attributed to the polar character of CF₃.