Computational study on kinetics and mechanism of Cl-initiated hydrogen abstraction of methyl fluoroacetate

Abstract

The reaction kinetics of the H-atom abstraction reaction of methyl fluoroacetate with Cl-atoms are investigated at G2(MP2)//MPWB1K/6-31+G(d,p) level of theory. The rate constants of reactions are determined for the first time in a wide temperature range of 250–450 K. • Reactions between CH 2 FC(O)OCH 3 with Cl atoms are investigated. • The atmospheric lifetime of MFA is estimated to be 1.21 years. • PES are obtained at G2(MP2)//MPWB1K/6-31+G(d,p) level of theory. • Predicted rate constant is in good agreement with available experimental values. • Major contribution from the CH 2 F group. A theoretical investigation has been performed on the mechanism, kinetics and thermochemistry of the gas phase reactions of methyl fluoroacetate CH 2 FC(O)OCH 3 (MFA) with Cl atoms. Geometry optimization and frequency calculations have been made at the MPWB1K/6-31+G(d,p) level of theory and energetic information is further refined by calculating the energy of the species using G2(MP2) theory. The rate constant for reactions of MFA with Cl atoms are reported over wide range of 250–450 K using the Canonical Transition State Theory (CTST). The atmospheric lifetime of CH 2 FC(O)OCH 3 was estimated to be around 1.21 years with respect to reaction with Cl atoms. The rate constant obtained is compared with literature values for other similar species to establish reactivity trends. It is shown that the F-atom substitution decrease the reactivity of C H bond of esters.