Reaction of ketenyl radical with hydroxyl radical over C2H2O2 potential energy surface: A theoretical study

Abstract

Abstract The potential energy surface of C 2 H 2 O 2 for HCCO + OH bimolecular reactions and the unimolecular decomposition of hydroxyketene (HOCH C O) are investigated employing high-level quantum chemical methods. Variable reaction coordinate transition state theory is used for the high-pressure limit rate constant calculation of the main reaction channels and RRKM-based multiwell master equation is used to calculate the pressure dependent rate constants and product branching ratios of these channels. The predicted rate constants are in good agreement with the limited experimental data available in the literature. The product distribution analysis shows that the association/decomposition of HCCO + OH to the formation of CO + 1 HCOH and CO + 3 HCOH channels are dominant in the whole temperature range of 500–2000 K below 1 atm, whereas at higher pressure and low temperature, the association reaction producing 3 CHCOOH becomes competitive. For the unimolecular decomposition of hydroxyketene, the formation of CO + 1 HCOH channel is found to be predominant over a wide range of temperatures and pressures. Rate constants of these reactions and thermodynamic parameters for species involved in these reactions are also provided.