Improved Prediction of Octanol−Water Partition Coefficients from Liquid−Solute Water Solubilities and Molar Volumes

A volume-fraction-based solvent−water partition model for dilute solutes, in which the partition coefficient shows a dependence on solute molar volume ( ), is adapted to predict the octanol−water partition coefficient (Kow) from the liquid or supercooled-liquid solute water solubility (Sw), or vice versa. The established correlation is tested for a wide range of industrial compounds and pesticides (e.g., halogenated aliphatic hydrocarbons, alkylbenzenes, halogenated benzenes, ethers, esters, PAHs, PCBs, organochlorines, organophosphates, carbamates, and amides-ureas-triazines), which comprise a total of 215 test compounds spanning about 10 orders of magnitude in Sw and 8.5 orders of magnitude in Kow. Except for phenols and alcohols, which require special considerations of the Kow data, the correlation predicts the Kow within 0.1 log units for most compounds, much independent of the compound type or the magnitude in Kow. With reliable Sw and data for compounds of interest, the correlation provides an effective means for either predicting the unavailable log Kow values or verifying the reliability of the reported log Kow data.