Abstract |
The cosolvency of completely miscible organic solvents (CMOSs) and partially miscible organic solvents (PMOSs) on the solubility of hydrophobic organic chemicals (HOCs) was examined, with an emphasis on PMOSs. Measured solubilities were compared with predictions from the log-linear model and the UNIFAC model. In ternary mixed solvents, nonpolar PMOSs such as toluene and trichloroethylene did not appreciably increase HOC solubility. However, polar PMOSs such as o-cresol and nitrobenzene did significantly enhance HOC solubility. Polar PMOSs have greater cosolvent effect, not because they are stronger solvents, but because they are present in greater concentrations as a result of their higher aqueous solubilities (10,000 mg/L or 1% volume fraction). The cosolvency of CMOSs increases with decreasing solvent polarity, whereas the opposite is true for PMOSs. (Copyright (c) by the American Chemical Society, 1990.) |