Kinetics of the reaction of CH₃O₂ with ClO at 293 K

Abstract

The reaction of CH3O2 with ClO has been studied at 293 K using a flow reactor sampled by a mass spectrometer. Under conditions where [ClO] » [CH3O2], the CH3O2 decayed under pseudo‐first‐order conditions giving a rate coefficient of (1.9±0.4)×10−12 cm³ s−1. CH3OCl was detected as a reaction product. The implications of the measurements for the chemistry of the stratosphere are discussed briefly.

A computational investigation of the atmospheric reaction CH3O2+ClO

“…This allows the proper identification of this channel as the most important pathway, in agreement with the experimental evidence [2][3][4][5][6][7][8][9]. (b) The formation of methyl chlorate isomer as a reaction intermediate is found to be possible not only from the CH 3 OOClO isomerization [10] but also directly from the reactants through the newly determined transition state TS1 located at À2.3 kcal mol À1 .…”

“…However, other thermodynamically accessible channels have been also considered and investigated in subsequent studies [4,9] CH 3 Reaction enthalpy values, DH 298 , are taken from Helleis et al [4] with those in parentheses from Daële et al [9]. Thus, later experimental measurements [4][5][6][7][8][9] were able to identify methyl hypochloride, CH 3 OCl, among the reaction products, indicating that channel (1b) may also be a potentially important pathway with a considerable branching ratio at the low temperatures prevalent in the polar winter and early springtime stratosphere. The large discrepancies however, observed in the measured rate constant values of channels (1a) and (1b) [9], have created severe uncertainties about the real significance of each pathway.…”

“…The reaction of ClO with the methylperoxy radical in particular, is an interesting such system [2][3][4][5][6][7][8][9] with an important impact on stratospheric ozone chemistry and the CH 4 oxidation chain. The earlier experimental investigations had suggested that the main channel is the formation of methoxy radicals and chlorine peroxide, readily decomposing into molecular oxygen and active atomic chlorine [2,3].…”

The relevance of reactions of the methyl peroxy radical (CH₃O₂) and methylhypochlorite (CH₃OCl) for Antarctic chlorine activation and ozone loss

“…3.3.3 The heterogeneous reaction CH 3 OCl þ HCl. Kenner et al (1993) and Crowley et al (1994) suggested that the heterogeneous reaction CH 3 OCl þ HCl ! CH 3 OH þ Cl 2 (R22) might take place in analogy with the heterogeneous reaction R2.…”

Ab initio study of the potential energy surface and product branching ratios for the reaction of O(1D) with CH3CH2Br

“…However, in the upper atmosphere the reactions with atomic oxygen are of importance6. CH 3 CH 2 OBr is recognized to play a significant role in several of the processes involved in stratospheric ozone depletion cycles7–10. Thus, numerous studies have been devoted to the theoretical and experimental investigation of the properties of these compounds11–17.…”