| Abstract
| - The UV absorption spectra of CF3CHO, C2F5CHO, C3F7CHO, C4F9CHO, CF3CH2CHO, and C6F13CH2CHOwere recorded over the range 225−400 nm at 249−297 K. CxF2x+1CHO and CxF2x+1CH2CHO have broadabsorption features centered at 300−310 and 290−300 nm, respectively. The strength of the absorption increaseswith the size of the CxF2x+1 group. There was no discernible (<5%) effect of temperature on the UV spectra.Quantum yields for photolysis at 254 and 308 nm were measured. Quantum yields at 254 nm were 0.79 ±0.09 (CF3CHO), 0.81 ± 0.09 (C2F5CHO), 0.63 ± 0.09 (C3F7CHO), 0.60 ± 0.09 (C4F9CHO), 0.74 ± 0.08(CF3CH2CHO), and 0.55 ± 0.09 (C6F13CH2CHO). Quantum yields at 308 nm were 0.17 ± 0.03 (CF3CHO),0.08 ± 0.02 (C4F9CHO), and 0.04 ± 0.01 (CF3CH2CHO). The quantum yields decrease with increasingsize of the CxF2x+1 group and with increasing wavelength of the photolysis light. The photolysis quantumyield at 308 nm for CF3CHO measured here is a factor of at least 8 greater than that reported previously.Photolysis is probably the dominant atmospheric fate of CxF2x+1CHO (x = 1−4) and is an important fate ofCxF2x+1CH2CHO (x = 1 and 6). These results have important ramifications concerning the yield ofperfluorocarboxylic acids in the atmospheric oxidation of fluorotelomer alcohols.
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