Reactions of trifluoromethyl radicals with organic halides. Part 6.—Bromo- and fluoro-bromoethanes

Abstract

The reactions of CF₃ radicals with the compounds C₂H₆, C₂H₅Br, CH₃CHBr₂, CH₂BrCH₂Br, CH₂BrCH₂Cl, C₂H₅F, CH₃CF₂Br, CF₃CH₂Br, C₂F₅Br, CF₂HCF₂Br and CHF₂Br were studied to obtain Arrhenius parameters for H and Br abstraction by [graphic ommitted] No abstraction of F or Cl was detected. Several of the reactions involving bromoethanes are complicated by the elimination of HBr from the bromide, photosensitized by the hexafluoroacetone used as a source of CF₃ radicals. However, a technique for measuring reliable rate constants was developed. The variations in activation energies for H and Br abstraction are discussed in terms of enthalpy changes and polar effects.