Environmental assessment of CFC alternatives: Rate constants for the reactions of OH radicals with fluorinated compounds

Abstract

The rate constants for the reactions of OH radicals with CF 3OCHFCF 3, and CF 3CHFCF 3 have been measured over the temperature range 250–430 K. Kinetic measurements have been carried out using the flash photolysis, and laser photolysis methods combined, respectively, with the laser induced fluorescence technique. The influence of impurities in the samples has been investigated by using gas chromatography. No sizable effect of impurities was found on the measured rate constants of these fluorinated compounds, if the purified samples were used in the measurements. The following Arrhenius expressions were determined: k(CF 3OCHFCF 3) = (4.39 ± 1.38) × 10 −13 exp[−(1780 ± 100)/ T] cm 3 molecule −1 s −1, and k(CF 3CHFCF 3) = (6.19 ± 2.07) × 10 −13 exp[−(1830 ± 100)/ T] cm 3 molecule −1 s −1.