Atmospheric chemistry of CH 3Cl: mechanistic study of the reaction of CH 2ClO 2 radicals with HO 2

Abstract

Fourier transform infrared spectroscopy was used to identify CH 2ClOOH and HC(O)Cl as products of the gas phase reaction of CH 2ClO 2 radicals with HO 2 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 CH 2ClOOH 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 CH 2ClOOH was investigated; rate constants of k(Cl + HC(O)Cl) = (6.9 ± 2.1) × 10 −13 and k(Cl + CH 2ClOOH) = (5.9 −2.5 +0.9) × 10 −13 cm −3 molecule −1 s −1 were determined.