Secondary kinetics of methanol decomposition : theoretical rate coefficients for {sup 3}CH{sub 2} + OH, {sup 3}CH{sub 2} + {sup 3}CH{sub 2}, and {sup 3}CH{sub 2} + CH{sub 3}.
Direct variable reaction coordinate transition state theory (VRC-TST) rate coefficients are reported for the {sup 3}CH{sub 2} + OH, {sup 3}CH{sub 2} + {sup 3}CH{sub 2}, and {sup 3}CH{sub 2} + CH{sub 3} barrierless association reactions. The predicted rate coefficient for the {sup 3}CH{sub 2} + OH reaction ({approx} 1.2 x 10{sup -10} cm{sup 3} molecule{sup -1} s{sup -1} for 300-2500 K) is 4-5 times larger than previous estimates, indicating that this reaction may be an important sink for OH in many combustion systems. The predicted rate coefficients for the {sup 3}CH{sub 2} + CH{sub 3} and {sup 3}CH{sub 2} + {sup 3}CH{sub 2} reactions are found to be in good agreement with the range of available experimental measurements. Product branching in the self-reaction of methylene is discussed, and the C{sub 2}H{sub 2} + 2H and C{sub 2}H{sub 2} + H{sub 2} products are predicted in a ratio of 4:1. The effect of the present set of rate coefficients on modeling the secondary kinetics of methanol decomposition is briefly considered. Finally, the present set of rate coefficients, along with previous VRC-TST determinations of the rate coefficients for the self-reactions of CH{sub 3} and OH and for the CH{sub 3} + OH reaction, are used to test the geometric mean rule for the CH{sub 3}, {sup 3}CH{sub 2}, and OH fragments. The geometric mean rule is found to predict the cross-combination rate coefficients for the {sup 3}CH{sub 2} + OH and {sup 3}CH{sub 2} + CH{sub 3} reactions to better than 20%, with a larger (up to 50%) error for the CH{sub 3} + OH reaction.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 929245
- Report Number(s):
- ANL/CHM/JA-59379; JPCAFH; TRN: US200815%%248
- Journal Information:
- J. Phys. Chem. A, Vol. 111, Issue 35 ; Sep. 6, 2007; ISSN 1089-5639
- Country of Publication:
- United States
- Language:
- ENGLISH
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