Kinetic Study and Rate Coefficient Calculations of the Reaction of 1-Hydroxyethyl Radical with Nitric Oxide.

Abstract

The kinetic study of the reaction of 1-hydroxyethyl radicals (CH3CHOH) with nitric oxide (NO) was performed over the temperature range of 200-1100 K and the pressure range of 1.0 × 10-5 to 10.0 bar. The geometries of all of the stationary points were optimized at the B3LYP/6-311++G(df,pd) level of theory, and the energetics were refined at the CCSD(T)/cc-pVTZ level of theory. Eight reaction pathways were explored, and they all consisted of a common first step involving the formation of a deep potential well. Three favorable pathways were confirmed, and they were the channels producing the adducts CH3CO(NHOH) and CH3NOHCHO and the products H2O and CH3CNO. The Rice-Ramsperger-Kassel -Marcus-canonical variational transition state theory method with Eckart tunneling correction was used to calculate the rate coefficients of the system. The predicted total rate coefficients agree well with the available literature data and show negative temperature dependence and positive pressure dependence. The reaction producing the adduct CH3CHOHNO in the entrance channel is dominant at 1.0 bar, and its branching ratio is almost 100% at a temperature less than 670 K. At 3.0 Torr, it is only dominant at a temperature less than 600 K.