OH Reactivity and UV Spectra of Propane, n-Propyl Bromide, and Isopropyl Bromide

Kozlov, S. N., V. L. Orkin, R. E. Huie, and M. J. Kurylo (2003), OH Reactivity and UV Spectra of Propane, n-Propyl Bromide, and Isopropyl Bromide, J. Phys. Chem. A, 107, 1333-1338, doi:10.1021/jp021806j.

The rate constants for the reactions of OH radicals with the 1-bromopropane, 2-bromopropane, and propane were measured using the flash photolysis resonance fluorescence technique over the temperature range between 210 and 480 K. Arrhenius plots exhibit a noticeable curvature, and the rate constants can be represented using a three-parameter modified Arrhenius expression over the temperature range of the experiments with ca. 2% precision. Such a fit also describes the available high-temperature data for propane quite well. The best three-parameter fits to the data are: kC3H8(T) = 1.96×10-12×(T/298)1.83×exp{-167/T} cm3 molecule-1s-1; knPB(T) = 2.99×10-13×(T/298)2.79×exp{+369/T} cm3molecule-1s-1; and kiPB(T) = 1.66×10-13×(T/298)2.95×exp{+461/T} cm3molecule-1s-1. For the low temperature range of atmospheric interest, the reaction rate constants can be accurately presented by standard Arrhenius expressions. Based on the available low-temperature data the following rate constants can be recommended for the purpose of atmospheric modeling: kC3H8(T<300 K) = 8.66×10-12×exp{-615/T} cm3molecule-1s-1; knPB(T<300 K) = 3.03×10-12×exp{-330/T} cm3molecule-1s-1; kiPB(T < 300 K) = 1.77×10-12×exp{-260/T} cm3molecule-1s-1. Atmospheric lifetimes were estimated to be ca. 14, 14, and 19 days for CH3CH2CH3, CH2BrCH2CH3, and CH3CHBrCH3, respectively. The ultraviolet absorption spectra of these bromopropanes were measured between 164 and 270 nm.

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Upper Atmosphere Research Program (UARP)