Aqueous solutions of nonpolar molecules are notorious because of their eccentric thermodynamic properties (14,16,17,37,56), and because of our limited understanding of molecular interactions in the solutions (1, 2, 38, 56). It is well known that nonpolar substances are sparingly soluble in water, but the nature of the forces that tend to exorcise nonpolar molecules, or nonpolar groups, from water-the art of the insoluble (46)-is open to discussion, even at the thermodynamic level. The aim of this review is to illustrate the unique thermodynamic behavior of dilute aqueous solutions of small, nonpolar molecules, using available experimental data, and to discuss the interpretation of the data with particular reference to the thermodynamics of protein solutions. Kauzmann, in his classical review article (29), drew attention to the fact that interactions of water with nonpolar groups of protein molecules are involved in the stabilization of the conformations of proteins in aqueous solution. In order to elucidate such interactions Kauzmann suggested the study of the thermodynamic properties of solutions of small molecules, representative of the constituent groups of the proteins. Investigations of aqueous solutions of entirely nonpolar molecules, such as the hydro carbons, are, however, hampered by low solubility. Partly nonpolar [amphipatic (22) or amphiphilic (56)] molecules, for example the alcohols, may be highly soluble in water, but effects that are the result of interactions with the polar part of the molecules are predominant in the solutions. One therefore must face the fact that the experimental basis of discussions of interactions of water with nonpolar particles is loaded with uncertainties, and attempts to utilize experience, gained from working with solutions of
Search from 250 M+ research papersSearch from 250 M+ research papers
Feb 1, 1987
Ira Batra Garde 
Open Access