Atmospheric chemistry of perfluoroaldehydes (CxF2x+1CHO) and fluorotelomer aldehydes (CxF2x+1CH2CHO): Quantification of the important role of photolysis

作者：Chiappero Malisa S; Malanca Fabio E; Arguello Gustavo A^*; Wooldridge Steven T; Hurley Michael D; Ball James C; Wallington Timothy J; Waterland Robert L; Buck Robert C

来源：Journal of Physical Chemistry A, 2006, 110(43): 11944-11953.

DOI：10.1021/jp064262k

The UV absorption spectra of CF3CHO, C2F5CHO, C3F7CHO, C4F9CHO, CF3CH2CHO, and C6F13CH2CHO were recorded over the range 225-400 nm at 249-297 K. CxF2x+1CHO and CxF2x+1CH2CHO have broad absorption features centered at 300-310 and 290-300 nm, respectively. The strength of the absorption increases with 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 increasing size of the CxF2x+1 group and with increasing wavelength of the photolysis light. The photolysis quantum yield 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 CxF(2x+1)CHO (x = 1-4) and is an important fate of CxF2x+1CH2CHO (x = 1 and 6). These results have important ramifications concerning the yield of perfluorocarboxylic acids in the atmospheric oxidation of fluorotelomer alcohols.

• 出版日期2006-11-2