OH + (E)- and (Z)‑1-Chloro-3,3,3-trifluoropropene‑1 (CF₃CHCHCl) Reaction Rate Coefficients: Stereoisomer-Dependent Reactivity

Rate coefficients for the gas-phase reaction of the OH radical with (E)- and (Z)-CF₃CHCHCl (1-chloro-3,3,3-trifluoropropene-1, HFO-1233zd) (k₁(T) and k₂(T), respectively) were measured under pseudo-first-order conditions in OH over the temperature range 213–376 K. OH was produced by pulsed laser photolysis, and its temporal profile was measured using laser-induced fluorescence. The obtained rate coefficients were independent of pressure between 25 and 100 Torr (He, N₂) with k₁(296 K) = (3.76 ± 0.35) × 10^–13 cm³ molecule^–1 s^–1 and k₂(296 K) = (9.46 ± 0.85) × 10^–13 cm³ molecule^–1 s^–1 (quoted uncertainties are 2σ and include estimated systematic errors). k₂(T) showed a weak non-Arrhenius behavior over this temperature range. The (E)- and (Z)- stereoisomer rate coefficients were found to have opposite temperature dependencies that are well represented by k₁(T) = (1.14 ± 0.15) × 10^–12 exp[(−330 ± 10)/T] cm³ molecule^–1 s^–1 and k₂(T) = (7.22 ± 0.65) × 10^–19 × T² × exp[(800 ± 20)/T] cm³ molecule^–1 s^–1. The present results are compared with a previous room temperature relative rate coefficient study of k₁, and an explanation for the discrepancy is presented. CF₃CHO, HC­(O)­Cl, and CF₃CClO, were observed as stable end-products following the OH radical initiated degradation of (E)- and (Z)-CF₃CHCHCl in the presence of O₂. In addition, chemically activated isomerization was also observed. Atmospheric local lifetimes of (E)- and (Z)-CF₃CHCHCl, due to OH reactive loss, were estimated to be ∼34 and ∼11 days, respectively. Infrared absorption spectra measured in this work were used to estimate radiative efficiencies and well-mixed global warming potentials of ∼10 and ∼3 for (E)- and (Z)-CF₃CHCHCl, respectively, on the 100-year time horizon.