Theoretical investigation into the hydrogen abstraction reaction of CH₃CH₂F (HFC-161) with OH

A direct ab initio dynamics method is performed to study the mechanism and kinetics of the hydrogen abstraction reaction of CH₃CH₂F with OH. One transition state is located for α-H abstraction reaction, and two are identified for β-H abstraction. The optimized geometries and frequencies of the stationary points and the minimum-energy paths (MEPs) are calculated at the MP2/6-311G(d,p) level. To verify the reliability of MP2/6-311G(d,p) geometries, the optimizations of the reactants, products and transition states are also performed at the MPW1K/6-311+G(2df,2p) level. In order to obtain the 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 refined at G3 level based on the optimized geometries. The rate constants of the three channels are evaluated by using the canonical variational transition-state theory (CVT) with small-curvature tunneling (SCT) correction method over a wide temperature range of 210-3500 K.