Discussion of the mechanism of free‐radical pyrolyses of chloroethanes

Abstract

The mechanism usually proposed for the pyrolysis of l,2-CzH4Cl2 is discussed in terms of existing data on elementary rate constants and using the value log,,(k,, sec-') = -(20710 k 630)/4.58 T + (14.33 k0.47) measured in this work for the rate constant of the reactionThis discussion is extended to the free-radical pyrolysis of other chlorinated ethanes using recent literature data. The usual Rice-Herzfeld mechanism is questioned in view of the discrepancy between experimental results and values predicted from the knowledge of elementary rate constants of this mechanism.(*) Present address: Solvay Research Center, Neder-over-Heembeek, Brussels. Note added in proofWhile this paper was in the course of publication, a paper by Holbrook, Walker and Watson ( J . Chem. SOC. (B), 577 (1971)) on the pyrolysis of 1,2-dichloroethane was published which leads to similar conclusions. This unstabilized product was kindly supplied by the Solvay Research Center, Nederover-Heembeek, Brussels.