Cl-atom transfer from CFCl3 to the c-C6H11 radical. An indirect estimation of the CFCl2?Cl bond dissociation energy

The Cl-transfer reaction between CFCl₃ and c-C₆H₁₁ radicals (R) was studied in liquid cyclohexane (RH). The Arrhenius parameters for Cl abstraction were determined in the RH-CFCl₃ system versus the termination reaction between cyclohexyl radicals and competitively versus addition to C₂Cl₄ in the RH-CFCl₃-C₂Cl₄ system. The two sets of results are in very good agreement and give the following Arrhenius expression for the reaction R + CFCL₃ → RCl + CFCl₂ (2): where θ = 2.303RT in kcal/mol. Comparison with Cl-transfer data of other chloromethanes and chloroethanes shows that an increase in the C? Cl bond dissociation energy is the main cause of the reduced reactivity of CFCl₃. Based on a previously developed correlation, D(CFCl₂ ? Cl) is estimated to be equal to 74.4 kcal/mol.