ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The reactions of CH3 radicals with O(3P) and O2 have been studied at 295 K in a gas flow reactor sampled by a mass spectrometer. For the reaction between CH3 and O, conditions were such that [O] » [CH3] and the methyl radicals decayed under pseudo-first-order conditions giving a rate coefficient of (1.14 ± 0.29) × 10-10 cm3/s. The reaction between CH3 and O2 was studied in separate experiments in which CH3 decayed under pseudo-first-order conditions. In this case, the rate coefficient obtained increased with increasing concentration of the helium carrier gas. This was varied over the range of 2.5-25 × 1016 cm-3, resulting in values for the apparent two-body rate coefficient ranging from 1 × 10-14 to 5.2 × 10-14 cm3/s. No evidence was found for the production of HCHO by a direct two-body process involving CH3 + O2, and an upper limit of 3 × 10-16 cm3/s was placed on the rate coefficient for this reaction. The experimental results for the apparent two-body rate coefficient exhibit the curvature one would expect for an association reaction in the fall-off region. Calculations used to extrapolate these measurements to the low-pressure limit yield a value for k0 of (3.4 ± 1.1) × 10-31 cm6/s, which is more than a factor of 2 higher than previous estimates.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550140806
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