Kinetics and ab initio Studies of Hydrogen Abstraction Reaction "HNCO + HCO →NCO + CH2O"

Using the MP2 method at the 6-311G(d,p) level, the geometries of the reactants, transition state and products of the hydrogen abstraction reaction of isocyanic acid (HNCO) with formyl radical (HCO) have been optimized. Changes of bond lengths of interacting molecules and the stationary point structures were discussed along the minimum energy paths (MEP). It shows that the process of the N-H bond breaking and the C-H bond forming is a concerted reaction. The stationary point energies are corrected by QCISD(T,full) and the potential barrier calculated 91.47 kJ/mol is close to the experimental barrier 108.9 kJ/mol. The rate constants calculated by the CVT method have been carefully compared with the experimental data over the range temperature 500~2500 K.