Kinetics of methyl radical-hydroxyl radical collisions and methanol decomposition.
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.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 947070
- Report Number(s):
- ANL/CHM/JA-58003
- Journal Information:
- J. Phys. Chem. A, Journal Name: J. Phys. Chem. A Journal Issue: 19 ; 2007 Vol. 111; ISSN 1089-5639; ISSN JPCAFH
- Country of Publication:
- United States
- Language:
- ENGLISH
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