Kinetics and mechanisms for the reaction of hydroxyl radicals with trifluoroacetic acid under atmospheric conditions

Article abstract of DOI:10.1016/0009-2614(94)00802-7

The rate constant for the gas-phase reaction of the hydroxyl radical with trifluoroacetic acid has been determined over the temperature range 283-323 K using a relative rate technique.The results provide a value k(OH+CF3C(O)OH)=2.0*10^-13exp(-146+/-500/T) cm³molecule^-1s^-1 based on k(OH+C2H6)=7.8*10^-12exp(-1020+/-100/T) cm³molecule^-1s^-1 for the rate constant of the reference reaction.The OH-radical initiated oxidation of CF3C(O)OH was investigated at 298 K in oxygen at 1 atm total pressure using Fourier-transform infrared spectroscopy.The major carbon-containing products were C(O)F2, CF3O3CF3 and CO2 suggesting that the dominant reaction channel for loss of the CF3C(O)O radical, formed by hydrogen atom abstraction, is carbon-carbon bond cleavage.The results indicate that the gas-phase reaction of OH radicals with trifluoroacetic acid may provide a sink for this compound in the troposphere that cannot be neglected.