Theoretical investigations on the OH radical mediated kinetics of cis- and trans-CH3CF=CHF and CH3CH=CF2 over temperature range of 200-400K

Abstract

Global reactivity for the OH-radical mediated kinetics of three Hydrofluoroolefins (HFOs), cis-CH3CF=CHF, trans-CH3CF=CHF and CH3CH=CF2 was evaluated at the CCSD(T)/cc-pVTZ//M062x/6-31G+(d,p) level of theory. The overall kinetics was computed using the Canonical Variational Transition State Theory (CVT) in combination with Small Curvature Tunneling (SCT) and Interpolated Single Point Energy (ISPE) corrections over the temperature range of 200 and 400 K. The total rate coefficients (k, in units of cm3 molecule−1 sec−1) for the reaction of OH radical with these HFOs at 298 K were computed to be, k298Kcis−CHF=CFCH3+OH=1.69×10−12, k298Ktrans−CHF=CFCH3+OH=3.12×10−12, and k298KCF2=CHCH3+OH=5.40×10−12. To further corroborate the computed kinetics, thermodynamic parameters and branching ratios were also computed for all the reaction pathways. Atmospheric lifetimes, Radiative forcing (RF), Global Warming Potentials (GWP) and Photochemical Ozone Creation Potentials (POCP) of these HFOs were also calculated and are presented in this manuscript.