ESTIMATION OF WATER-ORGANIC INTERFACIAL-TENSIONS - A LINEAR FREE-ENERGY RELATIONSHIP ANALYSIS OF INTERFACIAL ADHESION

The work of adhesion between water and a series of immiscible organic Liquids has been found to obey a linear solvation free energy relation ship (LSER) on the basis of solute parameters for the organic compound . This relationship, together with the surface tensions of water and o f the pure organic liquids, allows reasonably accurate estimation of t he corresponding interfacial tensions and provides insight into the na ture of intermolecular forces at the water-organic interface. Furtherm ore, the similarity of this multiparametric LSER to that for partition ing of organic solutes between water and the gas phase (log L-W) leads to a much simpler two-parameter relationship. Estimation of the inter facial tension with this latter relationship requires a knowledge of o nly two parameters, log L-W and the surface tension of the pure organi c liquid. Since reasonably accurate group contribution methods are ava ilable for estimating both log L-W and surface tensions from molecular structure, this result provides a novel approach for a priori estimat ion of the water-organic interfacial tension directly from the chemica l structure of the organic compound itself.