Tropospheric degradation of 2,2,2 trifluoroethyl butyrate: Kinetic study of their reactions with OH radicals and Cl atoms at 298K

Theoretical study on mechanism, kinetics, and thermochemistry of the gas phase reaction of 2,2,2-trifluoroethyl butyrate with OH radicals at 298 K

“…Hence, our study predicts reaction channel 3 to be the major reaction channel. This conclusion is in conformity with the observation made by Blanco et al 12 …”

“…The total rate coefficient (k OH ) is, therefore, obtained from the addition of rate coefficients for the four channels: k OH = k 1 + k 2 + k 3 + k 4 . Our calculated total rate constant k OH is found to be 2.7 × 10 −12 cm 3 molecule −1 s −1 using the M06-2X/6-31+G(d,p) level of theory, which is in reasonable agreement with the experimental value of (1.3 ± 0.3) × 10 −12 cm 3 molecule −1 s −1 reported by Blanco et al 12 using the relative rate method and FTIR detection technique and 1.77 × 10 −12 cm 3 molecule −1 s −1 derived by Kwok and Atkinson 34 using the structure-activity relationship (SAR) method. The branching ratio for reaction channels (1-4) is found to be 0.1%, 5.2%, 93.7%, and 1.0%, respectively, at 298 K. This clearly indicates the dominance of H-abstraction from -CH 2 group (reaction channel 3) of TFEB molecule.…”

“…37 Taking the values of rate constants for k MCF 6.14 × 10 −15 cm 3 molecule −1 s −1 from Ref. 37 and calculated rate constant of k TFEB = 1.97 × 10 −12 cm 3 molecule −1 s −1 at 272 K, the estimated lifetime is found to be 6.8 days, which is in reasonable agreement with the reported value of 4 days by Blanco et al 12 The standard enthalpy of formation ( H • f 298 ) for TFEB and the radicals CH 3 CH 2 CH 2 C(O)OCHCF 3 (P1), CH 3 CH 2 CHC(O)OCH 2 CF 3 (P2), CH 3 CHCH 2 C(O)OCH 2 CF 3 (P3), and CH 2 CH 2 CH 2 C(O)OCH 2 CF 3 (P4) generated from hydrogen atom abstraction can be valuable information for understanding the mechanism and thermochemical properties of their reactions and most importantly for atmospheric modeling. These values are not known.…”

“…[8][9][10][11][12][13][14][15][16][17][18][19] In this work, kinetic and mechanistic studies have been performed at 298 K for the reaction of 2,2,2-trifluoroethyl butyrate, CH 3 CH 2 CH 2 C(O)OCH 2 CF 3 (TFEB) with OH radicals. To the best of our knowledge, there is only one experimental study reported by Blanco et al 12 They studied the hydrogen abstraction reactions of OH radicals with TFEB using relative rate method at 298 K and reported a rate constant of (1.3 ± 0.3) × 10 −12 cm 3 molecule −1 s −1 . However, this study provided only the total rate constant and it is difficult to predict the detailed mechanism, thermochemistry, and contribution of each reaction channel toward overall rate constant.…”

Theoretical investigation on mechanism and kinetics of the Cl-initiated hydrogen abstraction reactions of ethyl trifluoroacetate at 298 K

“…Therefore, it is necessary to understand the chemistry of fluorinated esters in the atmosphere in order to assess the environmental acceptability of HFEs as a plausible replacement for chlorofluorocarbons. The reaction mechanisms of FESs with atmospheric oxidants have been studied extensively both experimentally [20][21][22][23][24][25] and theoretically [26][27][28][29][30][31][32] and continue to receive considerable attention. FESs absorb strongly in the earthly infrared (IR) radiation region of 800-1,200 cm −1 .…”