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Mechanism and Rate Constants of the CH3+ CH2CO Reaction : A Theoretical Study

Semenikhin, A. S.; Shubina, E. G.; Savchenkova, A. S.; Chechet, I. V.; Matveev, S. G.; Konnov, A. A. LU and Mebel, A. M. (2018) In International Journal of Chemical Kinetics
Abstract

The mechanism of the reaction of ketene with methyl radical has been studied by ab initio CCSD(T)-F12/cc-pVQZ-f12//B2PLYPD3/6-311G** calculations of the potential energy surface. Temperature- and pressure-dependent reaction rate constants have been computed using the Rice-Ramsperger-Kassel-Marcus (RRKM)-Master Equation and transition state theory methods. Three main channels have been shown to dominate the reaction; the formation of the collisionally stabilized CH3COCH2 radical and the production of the C2H5 + CO and HCCO + CH4 bimolecular products. Relative contributions of the CH3COCH2, C2H5 + CO, and HCCO + CH4 channels... (More)

The mechanism of the reaction of ketene with methyl radical has been studied by ab initio CCSD(T)-F12/cc-pVQZ-f12//B2PLYPD3/6-311G** calculations of the potential energy surface. Temperature- and pressure-dependent reaction rate constants have been computed using the Rice-Ramsperger-Kassel-Marcus (RRKM)-Master Equation and transition state theory methods. Three main channels have been shown to dominate the reaction; the formation of the collisionally stabilized CH3COCH2 radical and the production of the C2H5 + CO and HCCO + CH4 bimolecular products. Relative contributions of the CH3COCH2, C2H5 + CO, and HCCO + CH4 channels strongly depend on the reaction conditions; the formation of thermalized CH3COCH2 is favored at low temperatures and high pressures, HCCO + CH4 is dominant at high temperatures, whereas the yield of C2H5 + CO peaks at intermediate temperatures around 1000 K. The C2H5 + CO channel is favored by a decrease in pressure but remains the second most important reaction pathway after HCCO + CH4 under typical flame conditions. The calculated rate constants at different pressures are proposed for kinetic modeling of ketene reactions in combustion in the form of modified Arrhenius expressions. Only rate constant to form CH3COCH2 depends on pressure, whereas those to produce C2H5 + CO and HCCO + CH4 appeared to be pressure independent.

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Contribution to journal
publication status
epub
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in
International Journal of Chemical Kinetics
publisher
John Wiley & Sons
external identifiers
  • scopus:85041493201
ISSN
0538-8066
DOI
10.1002/kin.21156
language
English
LU publication?
yes
id
d3eefccd-6e0e-4feb-b5c3-e4c14535da09
date added to LUP
2018-02-22 07:11:12
date last changed
2018-05-29 11:09:10
@article{d3eefccd-6e0e-4feb-b5c3-e4c14535da09,
  abstract     = {<p>The mechanism of the reaction of ketene with methyl radical has been studied by ab initio CCSD(T)-F12/cc-pVQZ-f12//B2PLYPD3/6-311G** calculations of the potential energy surface. Temperature- and pressure-dependent reaction rate constants have been computed using the Rice-Ramsperger-Kassel-Marcus (RRKM)-Master Equation and transition state theory methods. Three main channels have been shown to dominate the reaction; the formation of the collisionally stabilized CH<sub>3</sub>COCH<sub>2</sub> radical and the production of the C<sub>2</sub>H<sub>5</sub> + CO and HCCO + CH<sub>4</sub> bimolecular products. Relative contributions of the CH<sub>3</sub>COCH<sub>2</sub>, C<sub>2</sub>H<sub>5</sub> + CO, and HCCO + CH<sub>4</sub> channels strongly depend on the reaction conditions; the formation of thermalized CH<sub>3</sub>COCH<sub>2</sub> is favored at low temperatures and high pressures, HCCO + CH<sub>4</sub> is dominant at high temperatures, whereas the yield of C<sub>2</sub>H<sub>5</sub> + CO peaks at intermediate temperatures around 1000 K. The C<sub>2</sub>H<sub>5</sub> + CO channel is favored by a decrease in pressure but remains the second most important reaction pathway after HCCO + CH<sub>4</sub> under typical flame conditions. The calculated rate constants at different pressures are proposed for kinetic modeling of ketene reactions in combustion in the form of modified Arrhenius expressions. Only rate constant to form CH<sub>3</sub>COCH<sub>2</sub> depends on pressure, whereas those to produce C<sub>2</sub>H<sub>5</sub> + CO and HCCO + CH<sub>4</sub> appeared to be pressure independent.</p>},
  author       = {Semenikhin, A. S. and Shubina, E. G. and Savchenkova, A. S. and Chechet, I. V. and Matveev, S. G. and Konnov, A. A. and Mebel, A. M.},
  issn         = {0538-8066},
  language     = {eng},
  month        = {02},
  publisher    = {John Wiley & Sons},
  series       = {International Journal of Chemical Kinetics},
  title        = {Mechanism and Rate Constants of the CH<sub>3</sub>+ CH<sub>2</sub>CO Reaction : A Theoretical Study},
  url          = {http://dx.doi.org/10.1002/kin.21156},
  year         = {2018},
}