AbstractThe product distribution and the mechanism of the reaction of Cl atoms with 2,2,2‐trifluoroethyl 2,2,2‐trifluoroacetate (TFETFA; CF3C(O)OCH2CF3) were investigated using a 1080 L environmental chamber with in situ Fourier transform infrared (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 produced with estimated yields of 35 and 28%, respectively. No trifluoroacetic acid (TFA; 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) CC, CO, CH decomposition, and (c) a possible α‐ester rearrangement pathway. The negligible importance of the α‐ester channel, to produce TFA, was explained by the reduction of the stability of the five‐membered transition state of the α‐ester rearrangement. Atmospheric implications, particularly regarding the fluorocarboxylic acid formation, are discussed. Copyright © 2010 John Wiley & Sons, Ltd.