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

Research output: Contribution to journalArticle

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 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.

Details

Authors
  • A. S. Semenikhin
  • E. G. Shubina
  • A. S. Savchenkova
  • I. V. Chechet
  • S. G. Matveev
  • A. A. Konnov
  • A. M. Mebel
Organisations
External organisations
  • Samara National Research University
  • Florida International University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Inorganic Chemistry
Original languageEnglish
Pages (from-to)273-284
JournalInternational Journal of Chemical Kinetics
Volume50
Issue number4
Early online date2018 Feb 8
Publication statusPublished - 2018 Apr
Publication categoryResearch
Peer-reviewedYes