Atmospheric chemistry of Z- and E-CF3CH=CHCF3

The atmospheric fates of Z- and E-CF3CH=CHCF3 have been studied, investigating the kinetics and the products of the reactions of the two compounds with Cl atoms, OH radicals, OD radicals, and O3. FTIR smog chamber experiments measured: k(Cl + Z-CF3CH=CHCF3) = (2.59 ± 0.47) × 10−11, k(Cl + E-CF3CH=CHCF3) = (1.36 ± 0.27) × 10−11, k(OH + Z-CF3CH=CHCF3) = (4.21 ± 0.62) × 10−13, k(OH + E-CF3CH=CHCF3) = (1.72 ± 0.42) × 10−13, k(OD + Z-CF3CH=CHCF3) = (6.94 ± 1.25) × 10−13, k(OD + E-CF3CH=CHCF3) = (5.61 ± 0.98) × 10−13, k(O3 + Z-CF3CHCHCF3) = (6.25 ± 0.70) × 10−22, and k(O3 + E-CF3CH=CHCF3) = (4.14 ± 0.42) × 10−22 cm3 molecule−1 s−1 in 700 Torr of air/N2/O2 diluents at 296 ± 2 K. E-CF3CH=CHCF3 reacts with Cl atoms to give CF3CHClC(O)CF3 in a yield indistinguishable from 100%. Z-CF3CH=CHCF3 reacts with Cl atoms to give (95 ± 10)% CF3CHClC(O)CF3 and (7 ± 1)% E-CF3CH=CHCF3. CF3CHClC(O)CF3 reacts with Cl atoms to give the secondary product CF3C(O)Cl in a yield indistinguishable from 100%, with the observed co-products C(O)F2 and CF3O3CF3. The main atmospheric fate for Z- and E-CF3CH=CHCF3 is reaction with OH radicals. The atmospheric lifetimes of Z- and E-CF3CH=CHCF3 are estimated as 27 and 67 days, respectively. IR absorption cross sections are reported and the global warming potentials (GWPs) of Z- and E-CF3CH=CHCF3 for the 100 year time horizon are calculated to be GWP100 = 2 and 7, respectively. This study provides a comprehensive description of the atmospheric fate and impact of Z- and E-CF3CH=CHCF3.