Reactions of trifluoromethyl radicals with organic halides. Part 3.—Choloromethanes, using hexafluoroacetone as a source of radicals

Abstract

The reactions of CF₃ radicals with CH₂Cl₂, CHCl₃ and CCl₄ have been studied using hexafluoroacetone as a source of radicals. Arrhenius parameters have been measured for all the possible reactions involving abstraction of H or Cl by CF₃. The validity of the kinetic results is examined. In conjunction with previous work, it is found that the activation energy for H abstraction falls progressively along the series CH₄… CHCl₃, whereas more complex changes occur with Cl abstraction in the series CH₃Cl … CCl₄. The significance of these changes is discussed. CCl₃ radicals were produced by some of the reactions and CF₃CCl₃ and C₂Cl₆ were present in the products. For the combination and cross-combination reactions of CF₃ and CCl₃, it was found that ϕ= 2.0±0.5 independent of temperature in the range 132–296°C.