Article révisé par les pairs
Résumé : The gas-phase photochlorination of C2Cl4, C 2HCl5 has been studied in a static system. Two elementary rate constants and one complex rate constant have been measured by the rotating sector technique: C2Cl5+Cl2→C 2Cl6+Cl (3), log k3=-1186/T+8.31; 2C 2Cl5→C2Cl4+C2Cl 6 (8), log k8=-18/T+8.66; log (k7k 4/k2)=-3686/T+14.52. Rate measurements in steady light yield log (k3/k81/2)=-1177/T+3.98; log (k 3(k2/k7k4)1/2)=657/T+1. 05, where k2, k4 and k7 refer to C 2Cl4+Cl→C2Cl5 (2) C 2Cl5→C2Cl4+Cl (4) C 2Cl5+Cl→C2Cl6. (7) These results and numerous cross-checks prove definitely a Bodenstein-type mechanism for photochlorination reactions and also that reactions with impurities, the wall or other entities, e.g., Cl3, are within a high experimental precision completely negligible.