ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Using dimethyl peroxide as a thermal source of methoxy radicals overthe temperature range of 110-160°C, and the combination of methoxy radicals and nitrogen dioxide as a reference reaction: a value was determined of the rate constant for the reaction of methoxy radicals with oxygen: is independent of nitrogen dioxide or oxygen concentration and added inert gas (carbon tetrafluoride). No heterogeneous effects were detected. The value of k4 is given by the expression \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log }k_4 {\rm = 9}{\rm .0} \pm {\rm 0}{\rm .6 - 4}{\rm .8 } \pm {\rm 1}{\rm .1/}\theta {\rm (M}^{{\rm - 1}} \cdot \sec ^{ - 1}) $$\end{document} In terms of atmospheric chemistry, this corresponds to a value of 105.6 M-1·sec-1 at 298 K. Extrapolation to temperatures where the combustion of organic compounds has been studied (813 K) produces a value of 107.7 M-1·sec-1 for k4. Under these conditions, reaction (4) competes with hydrogen abstraction or disproportionation reactions of the methoxy radical and its decomposition (3): In particular k3 is in the falloff region under these conditions. It is concluded that reaction (4) takes place as the result of a bimolecular collision process rather than via the formation of a cyclic complex.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550111003
