Rate Constants for the Reactions between OH and Perfluorinated Alkenes

Published

February 20, 2011

Author(s)

Vladimir L. Orkin, Gregory A. Poskrebyshev, Michael J. Kurylo III

Abstract

The rate constants for the reactions of OH radicals with fully fluorinated alkenes containing different number of –CF3 groups next to olefinic carbon, CF2=CF2, CF2=CFCF3, CF3CF=CFCF3, (CF3)2C=CFC2F5 were measured using the flash photolysis resonance fluorescence technique between 230 K and 480 K to give the following expressions: kC2F4(250-480 K) = 1.3210-12(T/298)0.9exp(+600/T) cm3 molecule-1 s-1, kC3F6(230-480 K) = 9.7510-14(T/298)1.936exp(+922/T) cm3 molecule-1 s-1, ktrans-C4F8(230-370 K) = 7.5010-14(T/298)1.766exp(+612/T) cm3 molecule-1 s-1, kcis-C4F8(230-370 K) = 2.9910-14(T/298)2.606exp(+760/T) cm3 molecule-1 s-1, kC6F12(230-480 K) = 2.1710-15(T/298)3.90exp(+1044/T) cm3 molecule-1 s-1. The kinetics of OH reaction in the original sample of octofluoro-2-propene (a mixture of cis- and trans-isomers of CF3CF=CFCF3) was studied to give the “effective” reaction rate constant for the typically industrial mixture k(230-480 K) = 7.8910-14(T/298)1.709exp(+557/T) cm3 molecule-1 s-1. Based on these results, the atmospheric lifetimes were estimated to be 1.2 days, 5.3 days, 21 days, 34 days, and 183 days for CF2=CF2, CF3CF=CF2, trans-CF3CF=CFCF3, cis-CF3CF=CFCF3, and (CF3)2C=CFC2F5, respectively. The general pattern of halolalkene reactivity towards OH is discussed.

Citation

Chemphyschem

Pub Type

Journals

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Keywords

hydroxyl, perfluorinated alkenes, atmospheric lifetime

Citation

Orkin, V. , A., G. and Kurylo, M. (2011), Rate Constants for the Reactions between OH and Perfluorinated Alkenes, Chemphyschem, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=907046 (Accessed March 25, 2025)