Reaction Mechanism and Product Branching Ratios of OH+C2H3F Reaction: A Theoretical Study

Ab initio CCSD(T)/CBS//B3LYP/6-311G(d, p) calculations of the potential energy surface for possible dissociation channels of HOCbegin{document}$_2$end{document}Hbegin{document}$_3$end{document}F, as well as Rice-Ramsperger-Kassel-Marcus (RRKM) calculations of rate constants, were carried out, in order to predict statistical product branching ratios in dissociation of HOCbegin{document}$_2$end{document}Hbegin{document}$_3$end{document}F at various internal energies. The most favorable reaction pathway leading to the major CHbegin{document}$_2$end{document}CHO+HF products is as the following: OH+Cbegin{document}$_2$end{document}Hbegin{document}$_3$end{document}Fbegin{document}$rightarrow$end{document}i2begin{document}$rightarrow$end{document}TS14begin{document}$rightarrow$end{document}i6begin{document}$rightarrow$end{document}TS9begin{document}$rightarrow$end{document}i3begin{document}$rightarrow$end{document}TS3begin{document}$rightarrow$end{document}CHbegin{document}$_2$end{document}CHO+HF, where the rate-determining step is HF elimination from the CO bridging position via TS11, lying above the reactants by 3.8 kcal/mol. The CHbegin{document}$_2$end{document}O+CHbegin{document}$_2$end{document}F products can be formed by F atom migration from Cbegin{document}$_beta$end{document} to Cbegin{document}$_alpha$end{document} position via TS14, then H migration from O to Cbegin{document}$_alpha$end{document} position via TS16, and C-C breaking to form the products via TS5, which is 1.8 kcal/mol lower in energy than the reactants, and 4.0 kcal/mol lower than TS11.