A theoretical study on gas-phase reactions of CF3CH=CF2 with OH: mechanism, kinetics and insights

The mechanism and kinetics of the CF3CH=CF2 + OH reaction were studied by using density functional theory (DFT) and transition state theory (TST). All possible mechanisms are taken into account, including F-abstraction, H-abstraction and OH-addition/elimination. Results reveal that the OH-addition/elimination reaction of P1 (CF2O + CF3CH2) and P7 (CHF2 + CF3CHO) are the dominant reaction pathways. Other pathways on the potential energy surface (PES) are less competitive from the thermodynamic and kinetic consideration. Moreover, the kinetics of all the important pathways are analysed according to transition state theory (TST). The rate constants of IM1, IM2, IM3 and IM5 increases firstly and then decreases as the temperature increasing. The rate constants of P1 and P7 reveals positive temperature dependence. The calculated rate constants are consistent with the experimental value. The atmospheric lifetime of CF3CH=CF2 in the existence of OH is computed to be about 15.75 days, which is agreement with the experimental data.