摘要

A comprehensive study of several atmospheric degradation routes for two hydrofluoroalcohols, CF3(CH2)(x=1,2)CH2OH, is presented. The gas-phase kinetics of their reactions with hydroxyl radicals (OH) and chlorine (Cl) atoms are investigated by absolute and relative techniques, respectively. The room-temperature rate coefficients (+/-sigma, in cm(3) molecule(-1) s(-1)) k(OH) and k(Cl), are respectively (9.7 +/- 1.1) x 10(-13) and (1.60 +/- 0.45) x 10(-11) for CF3CH2CH2OH, and (2.62 +/- 0.32) x 10(-12) and (8.71 +/- 0.24) x 10(-11) for CF3(CH2)(2)CH2OH. Average lifetimes of CF3CH2CH2OH and CF3(CH2)(2)CH2OH due to the OH and Cl reactions are estimated to be 12 and 4 days, and greater than 20 and 4 years, respectively. Also, the IR and UV absorption cross sections of CF3(CH2)(x=1,2)CH2OH are determined in the spectral ranges of 500-4000 cm(-1) and 200-310 nm. Photolysis of CF3(CH2)(x=1,2)CH2OH in the actinic region (lambda >= 290 nm) is negligible compared to their homogeneous removal. Additionally, computational IR spectra are consistent with the experimental ones, thus giving high confidence in the obtained results. The lifetimes of CF3(CH2)(x=1,2)CH2OH and IR spectra reported herein allow the calculation of the direct global warming potential of these hydrofluoroalcohols. The contribution of CF3(CH2)(x)CH2OH to radiative forcing of climate change will be negligible.

  • 出版日期2010-12-17