Rate Constants for the Reactions of OH Radicals with the ( E)/( Z) Isomers of CFCl=CFCl and ( E)-CHF=CHF.

The rate constants for the OH radical reactions with halogenated ethenes were investigated experimentally and computationally. The rate constants for the reactions of OH radicals with (E)-CFCl=CFCl (k1), (Z)-CFCl=CFCl (k2), and (E)-CHF=CHF (k3) were measured using flash and laser photolysis methods. The temporal profile of the OH radical was monitored by a laser-induced fluorescence technique. Kinetic measurements were carried out over the temperature range of 250–430 K. Arrhenius rate constants were determined to be k1 = (1.67 ± 0.06) × 10–12·exp[(140 ± 10) K/T], k2 = (1.75 ± 0.04) × 10–12·exp[(140 ± 10) K/T], and k3 = (3.99 ± 0.15) × 10–12·exp[(260 ± 10) K/T] cm3 molecule–1 s–1. The quoted uncertainties are 95% confidence levels and do not include systematic errors. Infrared absorption spectra were measured at room temperature. The atmospheric lifetimes and the global warming potentials of (E)-CFCl=CFCl, (Z)-CFCl=CFCl, and (E)-CHF=CHF were estimated to be 4.3, 4.2, and 1.2 days and 0.035, 0.036, and 0.0...