Bimolecular OH Rate Constants of Organic Compounds in Solution 2. Measurements in 1,2,2-Trichlorotrifluoroethane Using Hydrogen Peroxide as an OH Source

Semivolatile organic compounds (SOC) occur in the troposphere either adsorbed at aerosol particles or in the free gas phase, depending on temperature, vapor pressure of the compound, and total particular surface. In order to estimate the abiotic degradation of such compounds, the OH reaction rate constant must be known, which cannot be measured directly in the gas phase at the relevant temperature due to experimental difficulties. In the method proposed here, the inert solvent 1,1,2-trichlorotrifluoroethane is used as the reaction medium and hydrogen peroxide as photolytic OH source. Relative reaction rates can be measured, using a reference compound of known kOH air. The relative rates can be converted into absolute ones due to the 1:1 relationship observed by Dilling, Gonsior, Boggs, and Mendoza (1988) Environ. Sci. Technol. 22, 1447-1453, between the relative rates in the inert solvent and those in the gas phase.