Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Castilla-La Mancha, Avda. Camilo José Cela, s/n. 13071 Ciudad Real, Spain.
Chemphyschem. 2010 Dec 17;11(18):4079-87. doi: 10.1002/cphc.201000365.
A comprehensive study of several atmospheric degradation routes for two hydrofluoroalcohols, CF(3)(CH(2))(x=1,2)CH(2)OH, 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 (±σ, in cm(3) molecule(-1) s(-1)) k(OH) and k(Cl), are respectively (9.7±1.1)×10(-13) and (1.60±0.45)×10(-11) for CF(3)CH(2)CH(2)OH, and (2.62±0.32)×10(-12) and (8.71±0.24)×10(-11) for CF(3)(CH(2))(2)CH(2)OH. Average lifetimes of CF(3)CH(2)CH(2)OH and CF(3)(CH(2))(2)CH(2)OH 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 CF(3)(CH(2))(x=1,2)CH(2)OH are determined in the spectral ranges of 500-4000 cm(-1) and 200-310 nm. Photolysis of CF(3)(CH(2))(x=1,2)CH(2)OH in the actinic region (λ≥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 CF(3)(CH(2))(x=1,2)CH(2)OH and IR spectra reported herein allow the calculation of the direct global warming potential of these hydrofluoroalcohols. The contribution of CF(3)(CH(2))(x)CH(2)OH to radiative forcing of climate change will be negligible.
本文对两种氢氟醇，CF(3)(CH(2))(x=1,2)CH(2)OH 的几种大气降解途径进行了全面研究。分别采用绝对和相对技术研究了它们与羟基自由基(OH)和氯原子(Cl)的气相反应动力学。室温下 CF(3)CH(2)CH(2)OH 和 CF(3)(CH(2))(2)CH(2)OH 的 OH 和 Cl 反应的速率系数(k(OH)和 k(Cl))分别为(9.7±1.1)×10(-13)和(1.60±0.45)×10(-11)cm(3)分子(-1) s(-1)，(2.62±0.32)×10(-12)和(8.71±0.24)×10(-11)cm(3)分子(-1) s(-1)。由于 OH 和 Cl 反应，CF(3)CH(2)CH(2)OH 和 CF(3)(CH(2))(2)CH(2)OH 的平均寿命估计分别为 12 天和 4 天，大于 20 年和 4 年。此外，在 500-4000 cm(-1)和 200-310 nm 的光谱范围内确定了 CF(3)(CH(2))(x=1,2)CH(2)OH 的 IR 和 UV 吸收截面。与均相去除相比，CF(3)(CH(2))(x=1,2)CH(2)OH 在光解区（λ≥290nm）的光解可以忽略不计。此外，计算的 IR 光谱与实验光谱一致，因此对获得的结果具有高度信心。本文报道的 CF(3)(CH(2))(x=1,2)CH(2)OH 的寿命和 IR 光谱允许计算这些氢氟醇的直接全球变暖潜能。CF(3)(CH(2))(x)CH(2)OH 对气候变化的辐射强迫贡献将可以忽略不计。
