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Atmospheric fate of CF 3 Br, CF 2 Br 2 , CF 2 ClBr, and CF 2 BrCF 2 BR

1991; American Geophysical Union; Volume: 96; Issue: D3 Linguagem: Inglês

10.1029/90jd02735

2156-2202

James B. Burkholder, Robert R. Wilson, Tomasz Gierczak, Ranajit K. Talukdar, S. A. McKeen, John J. Orlando, Ghanshyam L. Vaghjiani, A. R. Ravishankara,

Spectroscopy and Laser Applications

The temperature dependent UV absorption cross sections of the haloalkanes CF 3 Br, CF 2 ClBr, CF 2 Br 2 , and CF 2 BrCF 2 Br are reported. The UV absorption cross sections were measured over the temperature range 210 to 296 K and the wavelength range 190 to 320 run. Upper limits of the rate coefficients for the reactions of OH with CF 3 Br, CF 2 Br 2 , CF 2 ClBr, and CF 2 BrCF 2 Br were also determined using both pulsed photolysis and flow tube techniques. The rate coefficients at 296 K were found to be <1.2×10 −16 , <1.5×10 −16 , <5.0×10 −16 , and <1.5×10 −16 cm 3 molec −1 s −1 for CF 3 Br, CF 2 ClBr, CF 2 Br 2 , and CF 2 BrCF 2 Br, respectively. The UV absorption cross‐section data and OH reaction rate coefficients of these species were combined with a one‐dimensional model to yield atmospheric lifetimes of 65, 16, 3.2, and <20 years for CF 3 Br, CF 2 ClBr, CF 2 Br 2 , and CF 2 BrCF 2 Br, respectively.