ABSTRACT
Abstract: In a binary mixture of solvents A and B, the surroundings of a molecule of A (or of B) generally differ in terms of the relative amounts of A and B molecules from the bulk composition due to preferential solvation. An eminent method for studying this situation is the use of uctuation theory, in terms of the Kirkwood-Buff integrals derived from thermodynamic data, provided the latter are sufciently accurate. The interactions among the components are obtained from this approach when their relative sizes are taken into account. This method has been applied to a large number of binary aqueous-organic solvent mixtures as well as to nonaqueous mixtures and to a small number of ternary solvent mixtures. In some cases, the preferential solvation occurs beyond the rst solvation shell, for example, in aqueous mixtures of tetra hydro furan or acetonitrile, where self-interactions of the water molecules far outweigh those between water and organic cosolvent molecules. The merits and disadvantages of using the Kirkwood-Buff integral approach are briey compared with those of other approaches, such as the quasi-lattice, quasi-chemical one or the use of solvatochromic probes and other spectroscopic methods.
