Atmospheric fate and greenhouse warming potentials of HFC 236fa and HFC 236ea

The rate coefficient for the reaction OH + CF3CH2CF3 (1,1,1,3,3,3-hexafluoropropane, HFC236fa) was measured between 269 and 413 K using the pulsed photolysis-laser induced fluorescence technique to be k1 = (1.60 ± 0.40) × 10−12 exp (−(2450 ± 150)/T) cm3 molecule−1 s−1. The rate coefficient, k2b, for the destruction of CF3CH2CF3 via reaction with O(1D) was measured to be (4.5 ± 1.9) × 10−12 cm3 molecule−1 s−1 using the laser photolysis-resonance fluorescence technique. From these data, along with previously published rate coefficients for OH reaction with HFC236ea, the atmospheric lifetimes of HFC236fa and HFC236ea were calculated to be 210 and 8.1 years, respectively. The room temperature infrared absorption cross sections for these two compounds were measured over the range 650 to 1350 cm−1. The global warming potentials (GWPs) of HFC236fa and HFC236ea, respectively, were calculated to be 5610 and 2200 for a 20-year horizon and 5160 and 220 for a 500-year horizon.

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