Theoretical study of H-abstraction reaction of C2H5OH with NCO

A direct dynamics method is employed to study the mechanism and kinetics of the hydrogen abstraction reaction of C2H5OH with NCO. The optimized geometries and frequencies of the stationary points and the minimum-energy paths (MEPs) are obtained at the MP2/6-311G(d,p) level. In order to obtain more accurate potential energy surface (PES) information and provide more credible energy data for kinetic calculation, the single-point energies along the MEPs are further computed at QCISD(T)/6-311+G(d,p)//MP2/6-311G(d,p) level. The rate constants for three channels of title reaction are calculated by canonical variational transition state theory (CVT) with small-curvature tunneling (SCT) contributions over the wide temperature region 220-1500 K. The theoretical overall rate constants are in good agreement with the available experimental data. For the title reaction, the methylene-H abstraction channel is dominant, while the hydroxyl-H and methyl-H abstraction channels are negligible over the whole temperature region.