UNIFAC prediction of aqueous and nonaqueous solubilities of chemicals with environmental interest

The aqueous and nonaqueous solubilities of a vast number of chemicals with significant environmental roles have been predicted using the latest version of UNIFAC group interaction parameters. A few critical measurements to test specific UNIFAC calculations of nonaqueous solubilities are also reported. The chemicals included in the calculation have aqueous solubilities that span 11 orders of magnitude. Good agreement was observed between the UNIFAC-predicted and literature-reported aqueous solubilities for 11 groups of compounds, i.e., short-chain alkanes, alkenes, alcohols, chlorinated alkanes, alkyl benzenes, chlorinated benzenes, PAHs, PCBs, anilines, phenols, and organohalide insecticides (DDT and lindane). Similarly, UNIFAC successfully predicts the co-solvency of PCB in methanol/water solutions. The error between predicted and literature-reported aqueous solubilities was larger for three groups of chemicals: long-chain alkanes, phthalates, and chlorinated alkenes. The average absolute error in UNIFAC precision of aqueous solubilities is about 0.5 log unit, but the average absolute error is only about 0.2 log unit for chlorinated aromatic compounds in organic solvents.