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Mechanism and Rate Constants of the CH 3 + CH 2 CO Reaction: A Theoretical Study
Author(s) -
Semenikhin A. S.,
Shubina E. G.,
Savchenkova A. S.,
Chechet I. V.,
Matveev S. G.,
Konnov A. A.,
Mebel A. M.
Publication year - 2018
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21156
Subject(s) - chemistry , ketene , reaction rate constant , arrhenius equation , ab initio , potential energy surface , reaction mechanism , rrkm theory , activation energy , elementary reaction , transition state theory , computational chemistry , photochemistry , medicinal chemistry , kinetics , organic chemistry , physics , quantum mechanics , catalysis
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 3 COCH 2 radical and the production of the C 2 H 5 + CO and HCCO + CH 4 bimolecular products. Relative contributions of the CH 3 COCH 2 , C 2 H 5 + CO, and HCCO + CH 4 channels strongly depend on the reaction conditions; the formation of thermalized CH 3 COCH 2 is favored at low temperatures and high pressures, HCCO + CH 4 is dominant at high temperatures, whereas the yield of C 2 H 5 + CO peaks at intermediate temperatures around 1000 K. The C 2 H 5 + CO channel is favored by a decrease in pressure but remains the second most important reaction pathway after HCCO + CH 4 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 3 COCH 2 depends on pressure, whereas those to produce C 2 H 5 + CO and HCCO + CH 4 appeared to be pressure independent.