Abstraction of chlorine atoms from chloromethanes by the cyclohexyl radical

Abstract

Abstract The kinetics of chlorine atom abstraction from the chloromethanes (CM)CCl 4 , CHCl 3 , and CH 2 Cl 2 by radiolytically generated cyclohexyl radicals has been studied in the liquid phase by a competitive method. The halogen abstraction data have been put on an absolute basis by comparing the rates of the metathetical reactions with the known rate of addition of cyclohexyl radicals to C 2 Cl 4 . The following Arrhenius parameters were obtained: CM log A (CM)/ A (C 2 Cl 4) E (CM) E (C 2 Cl 4 )(kcal/mole) log A (CM)(1./mole·sec) E (CM) (kcal/mole) Temperaure Range(°K) CCl 4 0.72±0.02 −1.42±0.05 9.40±0.08 5.88±0.15 333–453 CHCl 3 0.77±0.06 2.86±0.01 9.45±0.12 10.16±0.11 392–492 CH 2 Cl 2 0.56±0.12 6.37±0.27 9.42±0.18 13.67 ± 0.37 463–543 The error limits are the standard deviations from least mean square Arrhenius plots. The possible application of the Evans–Polanyi relationship to chlorine atom abstraction reaction from CM is considered.