Thermochemistry and Kinetics for Alkyl + O2 Reactions in Hydrocarbon Oxidation

Document Type

Conference Proceeding

Publication Date

3-1-2002

Abstract

Thermodynamic properties of reactants, products, and transition states were determined by ab initio methods at the CBS-Q and G2 levels of theory based on the optimized geometry using B3LYP/6-31G(d,p) DFT and isodesmic reaction analysis. Rate coefficients for reactions of the energized peroxy adduct were obtained from canonical transition state theory. Reactions of the adduct involved intramolecular hydrogen shifts, concerted HO2 molecular elimination and subsequent reactions of the isomers formed include epoxide formation. Important product formation pathways involved pathways that were lower in energy than the initial reactants. The dominant reaction up to almost 1000 K was formation of the ethylperoxy adduct while the direct formation of ethylene and HO2 from the energized adduct dominated above 1000 K. The production of the hydroperoxyethyl isomer was much less likely than ethylperoxy, reflecting the lower pathway from ethylperoxy directly to ethylene, which bypassed hydroperoxyethyl. Important new kinetic applications for chain branching and low-temperature ignition were discussed.

Identifier

0344120264 (Scopus)

Publication Title

ACS Division of Fuel Chemistry Preprints

ISSN

05693772

First Page

219

Last Page

222

Issue

1

Volume

47

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