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

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.