Partial Miscibilities in Binary Solutions with Two Kinds of Specific Interactions

In this article, new Gibbs free energy of mixing is derived when there are specific interactions between sol- vent-solute molecules and between solute-solute molecules in binary solutions. It is asssumed that a probability of specific interactions satisfies a binomial distribution. Using this Gibbs free energy of mixing, we investigate possible types of partial miscibilities and show that Ω-shaped temperature-composition phase diagrams can exist. We calculate Ω-shaped temperature- composition phase diagram of water-2-butanol system and compare that with result calculated by the method of Hino 5 et al.