Solvation thermodynamics and the physical – chemical meaning of the constant in Abraham solvation equations

0045-6535/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.chemosphere.2011.11.073 ⇑ Address: Aquatic Ecology and Water Quality Man University, P.O. Box 47, 6700 AA Wageningen, (0)623879203; fax: +31 (0)88 3357775. E-mail address: paul.vannoort@wur.nl Abraham solvation equations find widespread use in environmental chemistry. Until now, the intercept in these equations was determined by fitting experimental data. To simplify the determination of the coefficients in Abraham solvation equations, this study derives theoretical expressions for the value of the intercept for various partition processes. To that end, a modification of the description of the BenNaim standard state into the van der Waals volume is proposed. Differences between predicted and fitted values of the Abraham solvation equation intercept for the enthalpy of solvation, the entropy of solvation, solvent–water partitioning, air-solvent partitioning, partitioning into micelles, partitioning into lipid membranes and lipids, and chromatographic retention indices are comparable to experimental uncertainties in these values. 2011 Elsevier Ltd. All rights reserved.