Determination of D[C6F5CH2—Br] by the toluene carrier method

Abstract

The pyrolysis of C6F5CH2Br has been studied by the toluene carrier technique over the temperature range 727–800 °C. Rate constants are based on analysis for residual parent compound by gas chromatography using an internal standard technique. In selected runs a material balance of 100 ± 2% was obtained for bromine based on C6F5CH2Br plus HBr. Within the limits of the experimental technique the process appears to be first order and homogeneous. In addition to HBr the other major products of the thermal decomposition are C6F5CH3, (C6F5CH2)2, C6F5CH2CH2C6H5, and (C6H5CH2)2. The Arrhenius equation obtained is[Formula: see text]The log A value is very close to the value of 14.6 recommended by Benson and O'Neal for the decomposition of C6H5CH2Br. The activation energy, 225 ± 6 kJ mol−1, should be a reasonable estimate of D[C6F5CH2—Br].