Atmospheric chemistry of ( <i>E</i> )-1,2-difluoroethene: kinetics and mechanisms of the reactions with Cl atoms, OH radicals and O ₃

Smog chamber experiments were used to investigate the kinetics and mechanisms of the Cl atom, OH radical and O₃ initiated oxidation of (<i>E</i>)-1,2-difluoroethene (CHFCHF) at (298 ± 2) K under atmospheric conditions. Relative and absolute rate methods were used to measure <i>k</i>(Cl + (<i>E</i>)-CHFCHF) = (1.00 ± 0.12) × 10^-10, <i>k</i>(OH + (<i>E</i>)-CHFCHF) = (8.42 ± 1.29) × 10^-12, and <i>k</i>(O₃ + (<i>E</i>)-CHFCHF) = (1.16 ± 0.07) × 10^-18 cm³ molecule^-1 s^-1 in 700 Torr of N₂/air diluent. A slight pressure dependence for the kinetics of the Cl initiated oxidation was observed: 13% reduction at 50 Torr compared to atmospheric pressure. The observed products from the reaction of (<i>E</i>)-CHFCHF with Cl were HC(O)F and the corresponding (<i>Z</i>)-CHFCHF isomer (14% at 700 Torr, 62% at 50 Torr total pressure). In the OH radical initiated oxidation, the major product observed was HC(O)F in a yield of (205 ± 8)%. The O₃ initiated oxidation leads to HC(O)F and HF in yields of (148 ± 4)% and (53 ± 2)%, respectively. As part of this study the chlorine kinetics of the <i>Z</i>-isomer of the title compound was determined as <i>k</i>(Cl + (<i>Z</i>)-CHFCHF) = (1.21 ± 0.25) × 10^-10 cm³ molecule^-1 s^-1. The photochemical ozone creation potential, the radiative efficiency, and global warming potentials are estimated, and the results are discussed in the context of the atmospheric chemistry of (<i>E</i>)-CHFCHF and other halogenated alkenes.