Atmospheric HFEs degradation in the gas phase: Reaction of HFE-7500 with Cl atoms at low temperatures

The discharge-flow technique was used to determine the temperature dependence of the rate constant of the reaction of HFE-7500 (n-C3F7CF(OC2H5)CF(CF3)2) with Cl atoms at 1 Torr pressure. The study has been carried out from 253 to 343 K to approach to the tropospheric temperature profile. At room temperature the measured rate constant is k1 = (2.2 ± 0.6) × 10−12 cm3 molecule−1 s−1 (error is 2σ + 15%). The Arrhenius expression derived from our results is k1 = (1.1 ± 0.6) × 10−10exp[(−1190 ± 270)/T] cm3 molecule−1 s−1 (errors are 2σ + 15%). The reaction proceeds through hydrogen abstraction with a measured yield of HCl of 0.98 ± 0.24 (error is 2σ + 15%). The atmospheric implications of this reaction have been evaluated and its significance has been evidenced.