The chloromethoxy radical: kinetics of the reaction with O2 and the unimolecular elimination of HCl at 306 K

The gas-phase kinetics of the CH2ClO radical, formed by flash photolysis of Cl2 in CH3Cl/O2/N2 mixtures, was investigated at 306 K and at total pressures from 5 to 35 Torr by time-resolved mass spectrometry. Reaction of CH2ClO with O2 to form HC(O)Cl and HO2, and unimolecular dissociation to HCl and HCO were both observed. The absolute rate coefficient for reaction of CH2ClO with O2 is (2.8±1.2)×10−13 cm3 molecule−1 s−1. The unimolecular dissociation is well into the fall-off, the rate coefficient increasing from 6×102 s−1 to 4×103 s−1 between 5 and 35 Torr.