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

• Published in: Chemical physics letters 1994-09, Vol.227 (1), p.39-44
• Main Authors: Carr, Sinéad, Treacy, Jack J., Sidebottom, Howard W., Connell, Richenda K., Canosa-Mas, Carlos E., Wayne, Richard P., Franklin, James
• Format: Article
• Language: English
• ISSN: 0009-2614; 1873-4448
• 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 of k(OH+CF 3C(O)(OH) = 2.0 × 10 −13 exp (−146±500/ T) cm 3 molecule −1 s −1 based on k(OH+C 2H 6)=7.8×10 −12 exp(−1020±100/ T) cm 3 molecule t−1 s −1 for the rate constant of the reference reaction. The OH-radical initiated oxidation of CF 3C(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)F 2, CF 3O 3CF 3 and CO 2, suggesting that the dominant reaction channel for loss of the CF 3C(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.