The chloromethoxy radical: kinetics of the reaction with O 2 and the unimolecular elimination of HCl at 306 K

Abstract

The gas-phase kinetics of the CH 2ClO radical, formed by flash photolysis of Cl 2 in CH 3Cl/O 2/N 2 mixtures, was investigated at 306 K and at total pressures from 5 to 35 Torr by time-resolved mass spectrometry. Reaction of CH 2ClO with O 2 to form HC(O)Cl and HO 2, and unimolecular dissociation to HCl and HCO were both observed. The absolute rate coefficient for reaction of CH 2ClO with O 2 is (2.8±1.2)×10 −13 cm 3 molecule −1 s −1. The unimolecular dissociation is well into the fall-off, the rate coefficient increasing from 6×10 2 s −1 to 4×10 3 s −1 between 5 and 35 Torr.