Theoretical investigations on the reaction of ethenol with triplet oxygen atom

The reaction of ethenol with triplet oxygen atom was investigated at the CCSD(T)/aug-cc-pVTZ//M06-2X/cc-pVTZ and CBS-QB3 level of theory. The multiwell multichannel potential energy surface (PES) was constructed. The rate constants were determined by using Master Equation/Rice-Ramsperger-Kassell-Marcus (ME/RRKM) method with Eckart tunnelling correction over a temperature range of 298-1200 K and a pressure range of 1-1000 torr. The beta-C-addition is the dominant channel at low temperature, while alpha-C-addition is competitive with increasing temperature but still not dominant. Furthermore, formic acid (FA) is almost the entire product of alpha-C-addition, but it is only a by-product in the ethenol + O(P-3) system. Channel-producing products of CHOHCHO via beta-C-addition are the main channel and its branching ratio is 88.5% at 298 K. The rate constants of the total and main channels have a positive temperature dependence and no significant pressure dependence. The proposed rate constants can be used in the combustion and atmospheric model development for related systems.