Accession Number:

ADA164154

Title:

Competing Unimolecular Reactions of Flame Radicals. I. Isomerization and Dissociation of the Methoxy Radical.

Descriptive Note:

Final technical rept.,

Corporate Author:

ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s):

Report Date:

1985-11-01

Pagination or Media Count:

30.0

Abstract:

Flame chemistry models for even simple chemical oxidations include hundreds of chemical reactions. The methoxy radical, CH30, appears as a constituent in chemical models that describe the oxidation of fuels, especially combustion systems. Ab initio electronic structure calculations provide chemical energy differences necessary for statistical mechanical rate coefficient estimates. We report the results of many-body perturbation theory results for two unimolecular reactions of the methoxy radical. Rate coefficient estimates for the dissociation H-atom scission, and isomerization 1,2-hydrogen shift reactions infer that these reactions compete at high temperatures. The results of this study do not provide a definitive demonstration that the isomerization reaction of the methoxy radical competes with the dissociation reaction. One simplified dynamical model suggests that the reactions do compete at high temperature. However, Troes model for two-channel thermal unimolecular reactions predicts that the isomerization reaction does not compete with the dissociation reaction. The latter result, however, depends strongly upon the details of the energy-transfer processes that control the low-pressure rates, and on the rather gross approximations weve used in applying that model.

Subject Categories:

  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE