Kinetics of the CCl3 + CH3 Radical−Radical Reaction

Abstract

The CCl3 + CH3 (1) cross-radical reaction was studied by laser photolysis/photoionization mass spectroscopy. Overall rate constants were obtained in direct real-time experiments in the temperature region 306−800 K and bath gas (helium) density region (3−12) × 1016 atoms cm-3. The observed rate constant of reaction 1 is independent of temperature and equal to (2.05 ± 0.30) × 10-11 cm3 molecule-1 s-1. Formation of C2H2Cl2 and C2H3Cl2 was detected; however, only the C2H3Cl2 radical can be identified as a product of reaction 1 on the basis of the experimental information since the contribution of reaction 1 to the signal of C2H2Cl2 could not be separated from that of the reaction of CCl2 with CH3 (CCl2 being a minor product of photolysis of all precursors of CCl3 used). The experimental values of the rate constant are in reasonable agreement with the prediction based on the “geometric mean rule”. A separate experimental attempt to determine the rate constant of the high-temperature CCl3 + O2 (10) reaction res...