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Title: Organic photochemistry. 20. A method for estimating gas-phase rate constants for reactions of hydroxyl radicals with organic compounds from their relative rates of reaction with hydrogen peroxide under photolysis in 1,1,2-trichlorotrifluoroethane solution

Journal Article · · Environ. Sci. Technol.; (United States)
DOI:https://doi.org/10.1021/es00177a010· OSTI ID:6158426

The reaction with hydroxyl radicals appears to be the major transformation route for many organic compounds in the atmosphere. To avoid the difficulties of measuring the rate constants for these reactions in the gas phase for some compounds, we have developed a solution-phase system for measuring relative rates. This system involves photolysis of continuously extracted 90% hydrogen peroxide into 1,1,2-trichlorotrifluoroethane solution, which contains two or more organic compounds, one of which serves as a reference standard whose gas-phase rate constant is known. Reasonable correlations (r/sup 2/ = 0.84, 0.87) were obtained between the relative solution-phase rates and the absolute gas-phase rate constants, which varied over 4 orders of magnitude for n-hexane, 2,2,4-trimethylpentane, cyclohexane, 1,1,1,-trichloroethane, cyclohexene, trichloroethene, tetra-chloroethene, ethyl acetate, toluene, n-propylbenzene, o-xylene, p-isopropyltoluene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, biphenyl, naphthalene, hexafluorobenzene, o-dichlorobenzene, m-dichlorobenzene, 1,2,4-trichlorobenzene, anisole, and nitrobenzene. This method allows estimations of the gas-phase rate constants to within 1 order of magnitude or better.

Research Organization:
Dow Chemical Company, Midland, MI (USA)
OSTI ID:
6158426
Journal Information:
Environ. Sci. Technol.; (United States), Vol. 22:12
Country of Publication:
United States
Language:
English