The mechanism and kinetics of the atmospheric oxidation of CF < sub > 3 < /sub > (CF < sub > 2 < /sub > ) < sub > 2 < /sub > CH CH < sub > 2 < /sub > (HFC-1447fz) by hydroxyl radicals: < em > ab initio < /em > investigation

Phys Chem Chem Phys. 2024 Mar 25. doi: 10.1039/d3cp06149c. Online ahead of print.ABSTRACTThe oxidation of 3,3,4,4,5,5,5-heptafluoro-1-pentene (HFC-1447fz) by hydroxyl radicals plays a crucial role in atmospheric conditions. By employing the CCSD(T)/cc-pVTZ//M06-2X/6-311++G(d,p) level of theory, the detailed reaction mechanism, kinetics and atmospheric implications of the degradation of HFC-1447fz by hydroxyl radicals were investigated. Compared to H-abstraction channels, the OH addition reaction is determined to be more favorable initial pathways in the degradation processes of HFC-1447fz. The overall rate coefficient of the degradation of HFC-1447fz by OH radicals is estimated to be 1.66 × 10-12 cm3 molecule-1 s-1 and the lifetime of HFC-1447fz is found to be 7 days at 298 K, which are in good agreement with the reported experimental results. The global warming potential (GWP) for HFC-1447fz on the 50, 100 and 500-year time horizons is estimated using the calculated rate coefficient. Furthermore, the mechanisms of the subsequent reactions of two OH-addition adducts have also been investigated. By TD-DFT calculations, it was found that eleven species can undergo photodissociation, while ten other species are photolytically stable under sunlight.PMID:38526437 | DOI:10.1039/d3cp06149c

Source: Health Physics - March 25, 2024 Category: Physics Authors: Youqing Yu Li Pan Qiyao Sun Jie Wang Source Type: research