Atmospheric degradation of CF3C(O)OCH2CF3 initiated by Cl atoms: Product yields and fate of CF3C(O)OCH2O(.)CF3 radicals

M. B. BLANCO, I. BARNES AND M. A TERUEL.

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY

JOHN WILEY & SONS LTD

Año: 2010 vol. 488 p. 135 - 139

0894-3230

The product distribution and the mechanism of the reaction of Cl atoms with 2,2,2-trifluoroethyl 2,2,2-trifluoroacetate (CF3C(O)OCH2CF3) were investigated using a 1080 L environmental chamber with in situ FTIR spectroscopy detection. The experiments were performed at (296 ± 2) K and atmospheric pressure (760 ± 10) Torr of synthetic air free of NOx. A yield of (45 ± 3) % was obtained for the CF3C(O)OC(O)CF3 formation. CF2O and CO were found to be secondary products with estimated yields of 35 and 28 %, respectively. No trifluoroacetic acid (CF3C(O)OH) was observed. The yields determined are rationalized in terms of the competitive reaction channels for the fluoroalcoxy radicals formed in the H-abstraction process: a) reaction with O2, b) C-C, C-O, C-H decomposition and c) a possible á-ester rearrangement pathway. The negligible importance of the á-ester channel, to produce trifluoroacetic acid, was explained by the reduction of the stability of the five-membered transition state of the á-ester rearrangement. Atmospheric implications, particularly regarding the fluorocarboxylic acid formation, are discussed.