Rate constants of gas-phase reactions of trans-cyc-CF2CF2CHFCHF- and cyc-CF2CF2CH2CHCl- with OH radicals at 253-328Â K

Rate constants k1 and k2, for the reactions of trans-cyc-CF2CF2CHFCHF- and cyc-CF2CF2CH2CHCl- with OH radicals at 253-328 K were determined to be (7.64 ± 2.96) × 10−13 exp[−(1350 ± 110)/T] and (5.25 ± 0.062) × 10−13 exp[−(730 ± 40)/T] cm3 molecule−1 s−1, respectively, by means of a relative-rate method. OH radicals were generated by UV photolysis of ozone under 200 Torr of an O3-H2O-O2-He gas mixture in an 11.5-dm3 reaction chamber. The tropospheric lifetimes of trans-cyc-CF2CF2CHFCHF- and cyc-CF2CF2CH2CHCl- were estimated at 6.7 and 1.0 years, respectively.