Measurement of the OH Reaction Rate Constants for CF₃CH₂OH, CF₃CF₂CH₂OH, and CF₃CH(OH)CF₃

Abstract

The OH reaction rate constants have been measured for CF3CH2OH, CF3CF2CH2OH, and CF3CH(OH)CF3 over the temperature range 250−430K. Kinetic measurements have been carried out using the discharge flow, laser photolysis, and flash photolysis methods, combined respectively with the laser-induced fluorescence technique to monitor the OH radical concentrations. The influence of impurities contained in the sample of CF3CF2CH2OH has been investigated by means of sample purification using gas chromatography. No sizable effect of impurities was found on the measured rate constants of these three fluorinated alcohols. The Arrhenius rate constants have been determined from the respective kinetic data as k(CF3CH2OH) = (2.00 ± 0.37) × 10-12 exp[−(890 ± 60)/T], k(CF3CF2CH2OH) = (1.40 ± 0.27) × 10-12 exp[−(780 ± 60)/T], and k(CF3CH(OH)CF3) = (6.99 ± 1.56) × 10-13 exp[−(990 ± 70)/T] cm3 molecule-1 s-1. A method of predicting the OH reaction rate constants for fluorinated alcohols, hydrofluorocarbons, alkanes, and alcohols has been proposed.