PREDICTION OF PARTITION-COEFFICIENTS BY SCALED PARTICLE THEORY

Partition coefficients of some simple nonpolar solutes like inert gases (He-Xe) and n-alkanes (CH4-C7H16) between water and some organic solvents like octanol, benzene, toluene, chlorobenzene, have been computed using a cavity based model of solute solvation. While free energies of cavity formation of these solutes in these solvents have been calculated by Scaled Particle Theory (SPT), the free energies of interaction have been calculated by Lennard-Jones (LJ) and inductive type interaction. Free energies of hydrophobic effects have been obtained from literature. The predicted values of partition coefficients are well in agreement with experimental values. Analysis of results indicate that, while cavity forming energies are dominating for the observed partitionary behaviour of small solutes, hydrophobic effects are prominent for larger solutes.