Intermolecular forces expressed in 1,2-dichloroethane-water partition coefficients - A solvatochromic analysis

The molecular parameters and intermolecular forces controlling partition coefficients (P) in the 1,2-dichloroethane (DCE)-water system have been studied. A set of 44 solutes was selected to allow a regular and broad exploration of property spaces. Log P-dee values were measured by the shake-flask method, centrifugal partition chromatography, and/or the pH-metric method. Linear solvation Gibbs-energy relationship (LSER) analyses showed that log P-dee values are controlled by the molecular volume of the solutes and by their H-bonding donor acidity and acceptor basicity, with a contribution from the latter parameters significantly greater than in n-octanol-water partition coefficients. The DCE-water system appears as a promising alternative to the alkane-water system for obtaining partition coefficients of interest in structure-permeation relationship studies.