Atmospheric chemistry of n-CxF2x+1CHO (x = 1, 2, 3, 4):: Fate of n-CxF2x+1C(O) radicals

Smog chamber/FTIR techniques were used to study the atmospheric fate of n-CxF2x+1C(O) (x = 1, 2, 3, 4) radicals in 700 Torr O-2/N-2 diluent at 298 +/- 3 K. A competition is observed between reaction with O-2 to form n-CxF2x+1C(O)O-2 radicals and decomposition to form n-CxF(2x+1) radicals and CO. In 700 Torr O-2/N-2 diluent at 298 +/- 3 K, the rate constant ratio, k(n-CxF2x+1C(O) + O-2 -> n-CxF2x+1C(O)O-2)/k(n-CxF2x+1C(O) -> n-CxF2x+1 + CO) = (1.30 +/- 0.05) x 10(-17), (1.90 +/- 0.17) x 10(-19), (5.04 +/- 0.40) x 10(-20), and (2.67 +/- 0.42) x 10(-20) cm(3) molecule(-1) for x = 1, 2, 3, 4, respectively. In one atmosphere of air at 298 K, reaction with O-2 accounts for 99%, 50%, 21%, and 12% of the loss of n-CxF2x+1C(O) radicals for x = 1, 2, 3, 4, respectively. Results are discussed with respect to the atmospheric chemistry of n-CxF2x+1C(O) radicals and their possible role in contributing to the formation of perfluorocarboxylic acids in the environment.