The elimination of hydrogen fluoride from chemically activated ethyl fluoride as a function of energy

Abstract

The synthesis of ethyl fluoride with three widely separated energy contents between 65 and 105 kcal. mole^–1 and a recent determination of the activation energy for the elimination of HF permits a comparison of calculated rates of decomposition with the experimental values for various energy contents. Calculations for ethyl chloride and ethyl bromide show that the Rice–Ramsperger–Kassel–Marcus treatment is not greatly dependent on an exact description of the activated complex. A simple model, based on modifications of existing frequencies in the active molecule, yields good agreement with previous results for ethyl chloride and bromide and the experimental results for ethyl fluoride. The relatively large rate predicted for ‘low’ energy contents, compared with those calculated from the classical RRK theory, is emphasised.