Automated reaction path discovery tools have been used to map out the C3H3O potential energy surface and determine the prevailing channels for oxidation of the propargyl radical with atomic oxygen. The energy of the stationary points was then evaluated at the CCSD(T)/CBS//ωB97X-D/6-311+G(d,p) level of electronic structure theory. The C3H3 + O total and individual product channel rate constants were evaluated with Rice-Ramsperger-Kassel-Marcus Master Equation calculations combined with variable reaction coordinate transition state theory assessment of barrierless entrance channels. The total reaction rate so determined is in quantitative agreement with experiments, highlighting the relevance of accounting for C3H3 + O recombination on the excited electronic state surface. C2HCHO (propynal) + H are predicted as the prevailing reaction products, followed by CH2CCO (propadienone) + H, with minor contributions from C2H2 + HCO and C2H3 + CO. The calculated rate constants have been utilized in kinetic simulations, which tested the impact of the C3H3 + O reaction on chemical reactivity in premixed laminar flames of acetylene, ethylene, allene, propyne, and benzene. The results displayed macroscopic changes of the model predictions at low pressures (< 0.1 atm) and rich conditions, a reduction in the consumption of propargyl via C3H3 + O, and a substantial decrease in the C2H2 + HCO reactivity to C2H3 + CO. The updated model showed an improved performance in predicting C2 species in the considered flames.
Mechanism and kinetics of the oxidation of propargyl radical by atomic oxygen
Della Libera, Andrea;Pratali Maffei, Luna;Cavallotti, Carlo
2024-01-01
Abstract
Automated reaction path discovery tools have been used to map out the C3H3O potential energy surface and determine the prevailing channels for oxidation of the propargyl radical with atomic oxygen. The energy of the stationary points was then evaluated at the CCSD(T)/CBS//ωB97X-D/6-311+G(d,p) level of electronic structure theory. The C3H3 + O total and individual product channel rate constants were evaluated with Rice-Ramsperger-Kassel-Marcus Master Equation calculations combined with variable reaction coordinate transition state theory assessment of barrierless entrance channels. The total reaction rate so determined is in quantitative agreement with experiments, highlighting the relevance of accounting for C3H3 + O recombination on the excited electronic state surface. C2HCHO (propynal) + H are predicted as the prevailing reaction products, followed by CH2CCO (propadienone) + H, with minor contributions from C2H2 + HCO and C2H3 + CO. The calculated rate constants have been utilized in kinetic simulations, which tested the impact of the C3H3 + O reaction on chemical reactivity in premixed laminar flames of acetylene, ethylene, allene, propyne, and benzene. The results displayed macroscopic changes of the model predictions at low pressures (< 0.1 atm) and rich conditions, a reduction in the consumption of propargyl via C3H3 + O, and a substantial decrease in the C2H2 + HCO reactivity to C2H3 + CO. The updated model showed an improved performance in predicting C2 species in the considered flames.File | Dimensione | Formato | |
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