Rate constants of gas-phase reactions of trans-cyc-CF 2CF 2CHFCHF– and cyc-CF 2CF 2CH 2CHCl– with OH radicals at 253–328 K

Abstract

Rate constants k 1 and k 2, for the reactions of trans-cyc-CF 2CF 2CHFCHF– and cyc-CF 2CF 2CH 2CHCl– 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] cm 3 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 O 3–H 2O–O 2–He gas mixture in an 11.5-dm 3 reaction chamber. The tropospheric lifetimes of trans-cyc-CF 2CF 2CHFCHF– and cyc-CF 2CF 2CH 2CHCl– were estimated at 6.7 and 1.0 years, respectively.