Kinetic Investigations on the Gas Phase Reaction of 2,2,2‐Trifluoroethylbutyrate with OH Radicals: An Experimental and Theoretical Study

Abstract

The temperature dependent rate coefficients for the reaction between 2,2,2‐trifluoroethylbutyrate (2,2,2‐TFEB) with OH radicals were measured as a function of temperature (268‐343 K) and pressure (400‐760 Torr; N2 and O2) using relative rate technique. The temperature dependent rate coefficients for the gas phase reaction of 2,2,2‐TFEB + OH were used to deduce the Arrhenius expression: k(268‐343 K) = (2.72 ± 1.3)×10−13 exp{(530± 72)/T}cm3 molecule−1 s−1. At 298 K, the rate coefficient for the title reaction was obtained to be (1.58 ± 0.42) ×10−12 cm3 molecule−1 s−1. Extensive computational calculations were also performed as a complement to the present experimental study using canonical variational transition state theory (CVT) with small curvature tunnelling (SCT) correction in combination with the CCSD(T)/CC‐PVDZ//M062X/6‐31+G(d,p) level of theory. The atmospheric lifetime of the test molecule due to its reaction with OH radical is about 3 days, which is short lived. And therefore, its contribution towards the global warming potentials can be insignificant. The ozone formation potential of the test molecule is calculated to be 0.229 ppm, which is again negligible.

Quantum Chemical and Chemical Kinetic Investigation on Hydrogen Abstraction Reactions of CF3CF2C(O)OCH3 and CHF2CF2C(O)OCH3 with OH Radicals and Fate of Haloalkoxy Radicals

“…After crossing the potential energy barrier, the hydrogen-bonded product complex is formed, resulting in the formation of products. 26,29,41,42,60 A similar reaction mechanism is also followed by the reaction 61…”

“…In the theoretical study of other fluorinated esters + OH reactions, the reaction starts by forming a reactant complex that passes through a potential energy barrier. After crossing the potential energy barrier, the hydrogen-bonded product complex is formed, resulting in the formation of products. ,,,, A similar reaction mechanism is also followed by the reaction CH 3 CH 2 C­(O)­OCH 3 + OH. There is a difference between potential barriers’ values.…”

“… a We have calculated only GWP values for these ester molecules. For the detailed kinetic study of these esters, refer to refs ,–, respectively. …”

“…There are several experimental and theoretical studies of OH radicals with hydrogenated esters, but limited information is available for FESs. In recent years, reactions of FESs with OH radicals and Cl atoms were studied extensively by both experimental and theoretical tools. ,,− …”