Atmospheric Chemistry of (CF3)2CF–C≡N: A Replacement Compound for the Most Potent Industrial Greenhouse Gas, SF6

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• 作者：Mads P. Sulbaek AndersenMildrid Kyte ; Simone Thirstrup Andersen ; Claus J. Nielsen ; Ole John Nielsen
• 刊名：Environmental Science & Technology
• 出版年：2017
• 出版时间：February 7, 2017
• 年：2017
• 卷：51
• 期：3
• 页码：1321-1329
• 全文大小：491K
• ISSN：1520-5851

文摘

FTIR/smog chamber experiments and ab initio quantum calculations were performed to investigate the atmospheric chemistry of (CF₃)₂CFCN, a proposed replacement compound for the industrially important sulfur hexafluoride, SF₆. The present study determined k(Cl + (CF₃)₂CFCN) = (2.33 ± 0.87) × 10^–17, k(OH + (CF₃)₂CFCN) = (1.45 ± 0.25) × 10^–15, and k(O₃ + (CF₃)₂CFCN) ≤ 6 × 10^–24 cm³ molecule^–1 s^–1, respectively, in 700 Torr of N₂ or air diluent at 296 ± 2 K. The main atmospheric sink for (CF₃)₂CFCN was determined to be reaction with OH radicals. Quantum chemistry calculations, supported by experimental evidence, shows that the (CF₃)₂CFCN + OH reaction proceeds via OH addition to −C(≡N), followed by O₂ addition to −C(OH)═N·, internal H-shift, and OH regeneration. The sole atmospheric degradation products of (CF₃)₂CFCN appear to be NO, COF₂, and CF₃C(O)F. The atmospheric lifetime of (CF₃)₂CFCN is approximately 22 years. The integrated cross section (650–1500 cm^–1) for (CF₃)₂CFCN is (2.22 ± 0.11) × 10^–16 cm² molecule^–1 cm^–1 which results in a radiative efficiency of 0.217 W m^–2 ppb^–1. The 100-year Global Warming Potential (GWP) for (CF₃)₂CFCN was calculated as 1490, a factor of 15 less than that of SF₆.