Atmospheric chemistry of CH3Cl: Mechanistic study of the reaction of CH2ClO2 radicals with HO2

Fourier transform infrared spectroscopy was used to identify CH2ClOOH and HC(O)Cl as products of the gas phase reaction of CH2ClO2 radicals with HO2 radicals. At 700 Torr and 295 +/- 2 K, branching ratios of k(1a)/k(1) = 0.27 +/- 0.05 and k(1b)/k(1) = 0.73 +/- 0.12 were obtained for the CH2ClOOH forming channel and the HC(O)Cl channel, respectively. Quoted errors are two standard deviations plus an estimate of systematic uncertainties. This result is discussed with respect to previous literature data and computer models of atmospheric chemistry. As part of this work, the reactivity of Cl atoms towards HC(O)Cl and CH2ClOOH was investigated; rate constants of k(Cl + HC(O)Cl) = (6.9 +/- 2.1) X 10(-13) and k(Cl + CH2ClOOH) = (5.9(-2.5)(+0.9)) X 10(-13) cm(3) molecule(-1) s(-1) were determined.