Mechanism of the OH+CH2CO reaction

Abstract

Potential energy surface for the reaction of hydroxyl radical with molecular ketene has been studied using the ab initio G3(MP2) method. Three distinct reaction mechanisms, namely direct hydrogen abstraction, olefinic carbon addition, and carbonyl carbon addition, are revealed. A total of seven primary product channels, H₂O+HCCO, CO+CH₂OH, HCO+CH₂O, H+(HCO)₂, H+CH(OH)CO, CO₂+CH₃ and CO+CH₃O, including the consideration of six intermediates, are detailed. Moreover, the branching ratios are calculated using the RRKM-TST procedure. The findings in this theoretical study are in agreement with the available experimental measurements. The calculations show that at higher temperatures the major product channel is direct hydrogen abstraction leading to H₂O and HCCO, whereas the formation of CO and CH₂OH dominates the title reaction at lower temperatures.