Atmospheric chemistry of perfluorinated aldehyde hydrates (n-CxF2x+1CH(OH)(2), x=1, 3, 4): Hydration, dehydration, and kinetics and mechanism of Cl atom and OH radical initiated oxidation

摘要

Smog chamber/Fourier transform infrared (FTIR) techniques were used to measure k(Cl+CxF2x+1CH(OH)(2)) (x = 1, 3, 4) = (5.84 +/- 0.92) x 10(-13) and k(OH+ CxF2x+1CH(OH)(2)) (1.22 +/- 0.26) x 10(-13) cm(3) molecule(-1) s(-1) in 700 Torr of N-2 or air at 296 +/- 2 K. The Cl initiated oxidation of CF3CH(OH)(2) in 700 Torr of air gave CF3COOH in a molar yield of 101 +/- 6%. IR spectra of CxF2x+1CH(OH)(2) (x = 1, 3, 4) were recorded and are presented. An upper limit of k(CF3CHO+H2O) < 2 x 10(-23) cm(3) molecule(-1) s(-1) was established for the gas-phase hydration of CF3CHO. Bubbling CF3CHO/air mixtures through liquid water led to > 80% conversion of CF3CHO into the hydrate within the approximately 2 s taken for passage through the bubbler. These results suggest that OH radical initiated oxidation of CxF2x+1CH(OH)(2) hydrates could be a significant source of perfluorinated carboxylic acids in the environment.