Kinetics study of the gas-phase reactions of CHF2CF2OCHF2 and CF3CHFCF2OCH2CF2CF3 with OH radicals at 253-328Â K

The rate constants, k1 and k2, for the reactions of CHF2CF2OCHF2 and CF3CHFCF2OCH2CF2CF3 with OH radicals were measured by means of a relative rate method as (7.58 ± 3.30) × 10−13 exp [−(1720 ± 130)/T] and (8.46 ± 1.83) × 10−13 exp [−(1460 ± 60)/T] cm3 molecule−1 s−1, respectively, at 253-328 K. The measurements were performed in an 11.5-dm3 reaction chamber. OH radicals were generated by UV photolysis of an O3-H2O-He mixture at 200 Torr. The tropospheric lifetimes of CHF2CF2OCHF2 and CF3CHFCF2OCH2CF2CF3 were estimated at 26.5 and 9.1 years.