CF₃H production from the ozonolysis of HCFOs: E- and Z-CF3CH=CHCl

As part of the green transition new technologies and chemical compounds are being introduced with lower climate impact. One example is the replacement of halogenated compounds with high global warming potentials (GWPs) using compounds with low GWPs. Halogenated olefins are a family of chemicals that has been developed as alternatives to high GWP hydrofluorocarbons (HFCs). The olefinic double bond provides a reaction site for atmospheric OH radicals, lowering the atmospheric lifetime and climate impact. There is interest in the possible production of trifluoromethane (CF₃H, GWP = 14,600) (IPCC, 2021) from atmospheric photolysis of CF₃CHO, an oxidation product from several hydrofluoroolefins (HFOs). In addition to reaction with OH, the double bond in HFOs is reactive towards other atmospheric oxidants, including chlorine and ozone. The production of CF₃H from the ozonolysis of different commercially relevant fluorinated olefins has been reported (McGillen et al., PNAS, 120, e2312714120, 2023). If CF₃H is formed in the ozonolysis of HFOs, it is plausible that it would also be formed in other halogenated olefins with a CF₃CH = moiety. HCFO-1233zd (CF₃CH=CHCl) is a widely used hydrochlorofluoroolefin (HCFO). We report the formation of CF₃H in molar yields of (6.1 ± 0.9) % and (6.4 ± 1.0) % in the ozonolysis of E- and Z-CF₃CH=CHCl, respectively. This finding is discussed in the context of the contribution of halogenated olefins to the radiative forcing of climate change.