The kinetic studies of the H-abstraction reaction of CF3CH(OH)CF3 with the OH radical, which is predicted to have two classes of possible reaction channels, were carried out. The minimum energy path and energetics were calculated at M062X/6-31+G (d,p) method. The rate coefficients for each reaction channels were evaluated by canonical variational transition state theory (CVT) with the small-curvature tunneling correction (SCT) and zero-curvature tunneling over the wide range of temperature of 200-3000 K. The temperature-dependent rate expression for the title reaction is obtained to be k(Total) = 2.60 × 10(-22)T(3.04) exp(372.45/T) cm(3) molecule(-1) s(-1); with k(298) = 3.54 × 10(-14) cm(3) molecule(-1) s(-1). The global warming potentials (GWPs) and atmospheric lifetimes of CF3CH(OH)CF3 are computed in the present investigation. The atmospheric implications and the degradation mechanism of CF3CH(OH)CF3 are discussed. It is concluded that this compound can be suggested as an acceptable substitute to HFCs in terms of its atmospheric lifetime and GWPs.

The gas phase temperature dependent rate coefficients of Cl atoms with 2,2,2-trifluoroethylbutyrate, CH3CH2CH2C(O)OCH2CF3, were measured in the temperature range 268-343 K, at atmospheric pressures using the relative rate method, with ethyl acetate and ethane as reference compounds. The temperature dependent rate coefficients for the reaction of 2,2,2-TFEB + Cl were measured and were used to deduce the Arrhenius expression: k268-343K = [(4.42 ± 0.01) × 10(-19)]T(2.6) exp{(1132 ± 566)/T} cm(3) molecule(-1) s(-1). At 298 K, the rate coefficient for the title reaction is (4.54 ± 2.87) × 10(-11) cm(3) molecule(-1) s(-1), which is in good agreement with a previously reported value at 298 K. To complement our experimental results over the studied temperature range, theoretical kinetic calculations were also performed for the title reaction using canonical variational transition state theory (CVT) with small curvature tunneling (SCT) corrections in combination with the CCSD(T)/cc-pVDZ//M062X/6-31+g(d,p) level of theory. The temperature dependent Arrhenius expression was obtained to be k(T) = (1.89 ± 2.64) × 10(-21)T(3.4) exp{(1321 ± 111)/T} cm(3) molecule(-1) s(-1). The branching ratios, atmospheric implications, and degradation mechanism of 2,2,2-trifluoroethylbutyrate, CH3CH2CH2C(O)OCH2CF3, were discussed in detail in this manuscript.

The rate coefficient for the gas-phase reaction of Cl atoms with p-cymene was determined as a function of temperature (288-350 K) and pressure (700-800 Torr) using the relative rate technique, with 1,3-butadiene and ethylene as reference compounds. Cl atoms were generated by UV photolysis of oxalyl chloride ((COCl)2) at 254 nm, and nitrogen was used as the diluent gas. The rate coefficient for the reaction of Cl atoms with p-cymene at 298 K was measured to be (2.58 ± 1.55) × 10(-10) cm(3) molecule(-1) s(-1). The kinetic data obtained over the temperature range 288-350 K were used to derive an Arrhenius expression: k(T) = (9.36 ± 2.90) × 10(-10) exp[-(488 ± 98)/T] cm(3) molecule(-1) s(-1). Theoretical kinetic calculations were also performed for the title reaction using canonical variational transition state theory (CVT) with small curvature tunneling (SCT) between 250 and 400 K. The calculated rate coefficients obtained over the temperature range 250-400 K were used to derive an Arrhenius expression: k(T) = 5.41 × 10(-13) exp[1837/T] cm(3) molecule(-1) s(-1). Theoretical study indicated that addition channels contribute maximum to the total reaction and H-abstraction channels can be neglected. The atmospheric lifetime (τ) of p-cymene due to its reactions with various tropospheric oxidants was estimated, and it was concluded that the reactions of p-cymene with Cl atoms may compete with OH radicals in the marine boundary layer and in coastal urban areas where the concentration of Cl atoms is high.

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.

The gas-phase kinetics for the reactions of OH radicals and Cl atoms with 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HF2M2P) were measured at temperatures between 268 and 363 K using the relative rate experimental technique. Methane and acetonitrile were used as reference compounds to measure the rate coefficients of the title reactions. For the reactions of HF2M2P with OH radicals and Cl atoms, the rate coefficients were measured to be ( 7.07 ± 1.21) × 10 −15 and (2.85 ± 0.54) × 10 −14 cm 3 molecule −1 s −1 , respectively, at 298 K. The obtained Arrhenius expressions for the reactions of HF2M2P with OH radicals and Cl atoms are k HF2M2P + OH Exp − (268 − 363 K) = (7.84 ± 0.75) × 10 −14 exp [−(717 ± 59)/T] and k HF2M2P + Cl Exp − (268 − 363 K) = (3.21 ± 0.45) × 10 −12 exp [−(1395 ± 83)/T] cm 3 molecule −1 s −1 .In addition to the experimental measurements, computational kinetic calculations were also performed for the title reactions at the M06-2X/MG3S//M06-2X/6-31 + G(d,p) level of theory using advanced methods such as the canonical variational transitionstate theory coupled with small curvature tunneling corrections at temperatures between 200 and 400 K. Theoretical calculations reveal that the H-abstraction from the CH 3 group is a more favorable reaction channel than that from the OH group. Thermochemistry, branching ratios, cumulative atmospheric lifetime, global warming potential, acidification potential, and photochemical ozone creation potential of HF2M2P were calculated in the present investigation.