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Title: Kinetics of methyl radical-hydroxyl radical collisions and methanol decomposition.

Abstract

The CH{sub 3} + OH bimolecular reaction and the dissociation of methanol are studied theoretically at conditions relevant to combustion chemistry. Kinetics for the CH{sub 3} + OH barrierless association reaction and for the H + CH{sub 2}OH and H + CH{sub 3}O product channels are determined in the high-pressure limit using variable reaction coordinate transition state theory and multireference electronic structure calculations to evaluate the fragment interaction energies. The CH{sub 3} + OH {yields} {sup 3}CH{sub 2} + H{sub 2}O abstraction reaction and the H{sub 2} + HCOH and H{sub 2} + H{sub 2}CO product channels feature localized dynamical bottlenecks and are treated using variational transition state theory and QCISD(T) energies extrapolated to the complete basis set limit. The {sup 1}CH{sub 2} + H{sub 2}O product channel has two dynamical regimes, featuring both an inner saddle point and an outer barrierless region, and it is shown that a microcanonical two-state model is necessary to properly describe the association rate for this reaction over a broad temperature range. Experimental channel energies for the methanol system are reevaluated using the Active Thermochemical Tables (ATcT) approach. Pressure dependent, phenomenological rate coefficients for the CH{sub 3} + OH bimolecular reaction and for methanolmore » decomposition are determined via master equation simulations. The predicted results agree well with experimental results, including those from a companion high-temperature shock tube determination for the decomposition of methanol.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
947070
Report Number(s):
ANL/CHM/JA-58003
Journal ID: ISSN 1089-5639; JPCAFH; TRN: US200903%%1019
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Phys. Chem. A; Journal Volume: 111; Journal Issue: 19 ; 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
10 SYNTHETIC FUELS; CHEMISTRY; COMBUSTION; DISSOCIATION; ELECTRONIC STRUCTURE; EXPERIMENTAL CHANNELS; KINETICS; METHANOL; RADICALS; SHOCK TUBES

Citation Formats

Jasper, A. W., Klippenstein, S. J., Harding, L. B., Ruscic, B., and Chemistry. Kinetics of methyl radical-hydroxyl radical collisions and methanol decomposition.. United States: N. p., 2007. Web. doi:10.1021/jp067585p.
Jasper, A. W., Klippenstein, S. J., Harding, L. B., Ruscic, B., & Chemistry. Kinetics of methyl radical-hydroxyl radical collisions and methanol decomposition.. United States. doi:10.1021/jp067585p.
Jasper, A. W., Klippenstein, S. J., Harding, L. B., Ruscic, B., and Chemistry. Mon . "Kinetics of methyl radical-hydroxyl radical collisions and methanol decomposition.". United States. doi:10.1021/jp067585p.
@article{osti_947070,
title = {Kinetics of methyl radical-hydroxyl radical collisions and methanol decomposition.},
author = {Jasper, A. W. and Klippenstein, S. J. and Harding, L. B. and Ruscic, B. and Chemistry},
abstractNote = {The CH{sub 3} + OH bimolecular reaction and the dissociation of methanol are studied theoretically at conditions relevant to combustion chemistry. Kinetics for the CH{sub 3} + OH barrierless association reaction and for the H + CH{sub 2}OH and H + CH{sub 3}O product channels are determined in the high-pressure limit using variable reaction coordinate transition state theory and multireference electronic structure calculations to evaluate the fragment interaction energies. The CH{sub 3} + OH {yields} {sup 3}CH{sub 2} + H{sub 2}O abstraction reaction and the H{sub 2} + HCOH and H{sub 2} + H{sub 2}CO product channels feature localized dynamical bottlenecks and are treated using variational transition state theory and QCISD(T) energies extrapolated to the complete basis set limit. The {sup 1}CH{sub 2} + H{sub 2}O product channel has two dynamical regimes, featuring both an inner saddle point and an outer barrierless region, and it is shown that a microcanonical two-state model is necessary to properly describe the association rate for this reaction over a broad temperature range. Experimental channel energies for the methanol system are reevaluated using the Active Thermochemical Tables (ATcT) approach. Pressure dependent, phenomenological rate coefficients for the CH{sub 3} + OH bimolecular reaction and for methanol decomposition are determined via master equation simulations. The predicted results agree well with experimental results, including those from a companion high-temperature shock tube determination for the decomposition of methanol.},
doi = {10.1021/jp067585p},
journal = {J. Phys. Chem. A},
number = 19 ; 2007,
volume = 111,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}