NASA - National Aeronautics and Space Administration

Measurements of the rate constant for the gas-phase reactions of OH radicals with trans-1-chloro-3,3,3-trifluoropropene (trans-CHCl=CHCF₃) were performed using a flash photolysis resonance−fluorescence technique over the temperature range 220−370 K. The reaction rate constant exhibits a noticeable curvature of the temperature dependence in the Arrhenius plot, which can be represented by the following expression: k(220−370 K) = 1.025×10⁻¹³×(T/298)^2.29×exp(+384/T) cm³molecule⁻¹s⁻¹. The room-temperature rate constant was determined to be k(298 K) = (3.29 ± 0.10)×10⁻¹³ cm³molecule⁻¹s⁻¹, where the uncertainty includes both two standard errors (statistical) and the estimated systematic error. For atmospheric modeling purposes, the rate constant below room temperature can be represented by the following expression: k(220−298 K) = (7.20 ± 0.46)×10⁻¹³×exp[−(237 ± 16)/T] cm³molecule⁻¹s⁻¹. There was no difference observed between the rate constants determined at 4 kPa (30 Torr) and 40 kPa (300 Torr) at both 298 and 370 K. The UV and IR absorption cross sections of this compound were measured at room temperature. The atmospheric lifetime, global warming potential, and ozone depletion potential of trans-CHCl=CHCF₃ were estimated.