Molecular insights for the HFO-1345fz +X (X = Cl, O3 or NO3[rad]) reaction and fate of alkoxy radicals initiated by Cl: DFT investigations

Abstract

In the present work we investigate the reactions of HFO-1345fz (CF3CF2CH=CH2) with atomic Cl, O3 molecule and NO3 radical employing the CCSD(T)/6-311G(d,p)//M06-2x/6-311++G(d,p) theory. Addition and abstraction reaction channels are considered. The rate constants for the abstraction channel are derived from the transition state theory whereas the variational transition state model was applied to estimate the rate constants for the addition channel over the temperature range 200–1000K. It has been shown that the reaction occurs predominantly via addition to unsaturated carbon of HFO-1345fz. Calculated rate constants accompanying the reaction of HFO-1345fz with the Cl atom turns out to be 1.07×10−10cm3molecule−1sec−1 compared to 1.01×10−19cm3molecule−1sec−1 for O3 and 2.32×10−18cm3molecule−1sec−1 in case of the NO3. Calculated rate constants compare well with the experiments reported earlier. The atmospheric implications and secondary reactions (atmospheric decomposition of alkoxy radical) of the primary product initiated by Cl atom have further been analyzed. The product branching ratio and atmospheric lifetimes are given.