593-78-2Relevant academic research and scientific papers
Kinetics and products of the reactions of CH3O2 with Cl and ClO
Daele,Poulet
, p. 1081 - 1099 (2007/10/03)
The mechanisms of the reactions CH3O2 + Cl → products (1) and CH3O2 + ClO → products (2) have been studied at 298 K using a discharge flow reactor coupled to laser induced fluorescence for the detection of CH3O, observed as a product of both reactions, and mass spectrometry for the detection of other species. In the kinetic study of reaction (1), the channel producing the Criegee radical, CH2O2, has been found to be preponderant compared to the CH3O forming channel : CH3O2 + Cl → CH3O + ClO (1a), k1a = (2.0 ± 0.4) × 10-11 cm3 molecule-1 s-1 and CH3O2 + Cl → CH2O2 + HCl (1b), k1b = (2.0 ± 0.4) × 1010 cm3 molecule-1 s-1. The study of reaction (2) aimed at identifying the reaction pathways : CH3O2 + ClO → CH3O + ClOO (2a) and CH3O2 + ClO → CH3OCl + O2 (2b). The branching ratio for the first channel has been determined : α2a = 0.3 ± 0.1. These results are compared with other recent literature data and their atmospheric implication is briefly discussed.
Determination of the Rate Constant and of Product Branching Ratios in the Reaction of CH3O2 with OCl between 233 and 300 K
Kukui, A. S.,Jungkamp, T. P. W.,Schindler, R. N.
, p. 1298 - 1302 (2007/10/02)
The reaction CH3O2 + OCl -> prod (1) has been investigated in the temperature range 233 - 300 K using discharge flow mass-spectrometric technique.A rate constant k1(300 K) = (2.5 +/- 0.3)10-12 cm3 molecule-1 s-1 has been obtained observing the pseudo-first-order decay of CH3O2 radicals.The observed temperature dependence is described by k1(233-300 K) = (2.0 +/- 0.1)10-12 exp((80 +/- 50)/T) cm3 molecule-1 s-1.The reaction channel (1a) CH3O2 + OCl -> CH3OCl + O2 leading to CH3OCl formation was identified and found to be negatively temperature dependent with k1a(233-300 K) = (1.5 +/- 0.3)*10-14 exp ((920 +/- 200)/T) cm3 molecule-1 s-1.It is shown that HCHO and HOCl result from the secondary reaction of OCl with CH3O. - Keywords: Chemical Kinetics / Elementary Reactions / Mass Spectrometry / Radicals
Temperature-Dependent Rate Constants and Product Branching Ratios for the Gas-Phase Reaction Between CH3O2 and ClO
Helleis, Frank,Crowley, John N.,Moortgat, Geert K.
, p. 11464 - 11473 (2007/10/02)
Kinetic and product branching data have been measured for the reaction of CH3O2 radicals with ClO in the temperature range 225-355 K using the discharge-flow/mass spectrometry technique.The pressure-independent overall reaction rate constant is described by k(12)(225-355 K) = (3.25 +/- 0.50) * 10-12 exp((-114 +/- 38)/T) cm3 molecule-1 s-1.Two reaction channels were identified, leading to CH3O + ClOO (12a) and CH3OCl + O2 (12b), respectively.The branching ratios, α12a = k12a/k12 and α12b = k12b/k12, are also independent of pressure and are described by α12a = (1.51 +/- 0.56) exp((-218 +/- 93)/T) and α12b = (0.080 +/- 0.059) exp((-377 +/- 178)/T).These expressions yield roughly equal rate constants of k12a and k12b of ca. 1 * 10-12 cm3 molecule-1 s-1 at the low temperatures prevalent in the polar winter and early springtime stratosphere.We thus identify CH3OCl as a potentially important species in ozone hole chemistry.
