Theoretical studies on mechanism and kinetics of the hydrogen-abstraction reaction of CF3C(O)OCH2CH3 with OH radicals

• The hydrogen-abstraction mechanism of the CF3C(O)OCH2CH3 + OH reaction was investigated.
• Two conformers of CF3C(O)OCH2CH3 were considered in the kinetic calculation.
• The individual ICVT/SCT rate constants for each H-abstraction channel were evaluated.

The hydrogen-abstraction reaction of CF3C(O)OCH2CH3 + OH has been studied theoretically by a dual-level direct dynamics method. For the two stable conformers (I, II) of CF3C(O)OCH2CH3, three distinct transition states are identified for the reaction of conformer I (Cs symmetry) + OH (R1), and five transition states are ascertained for the reaction of conformer II (C1 symmetry) + OH (R2). The potential energy surface information for the kinetic calculation is obtained at the MCG3-MPWB//M06-2X/aug-cc-pVDZ level. The rate constants for each reaction channel are calculated using improved canonical variational transition-state theory (ICVT) with small-curvature tunneling correction (SCT) and are fitted by a three-parameter Arrhenius equation within 200–1000 K. The calculated rate constant is in reasonable agreement with the experimental data at 298 K.

Schematic potential energy surfaces for both the CF3C(O)OCH2CH3 (I) + OH and the CF3C(O)OCH2CH3 (II) + OH reactions.Figure optionsDownload as PowerPoint slide