Thermodynamics of mixtures containing a very strongly polar compound. Part II. Solid-liquid equilibria for sulfolane + nitrile systems and characterization of the sulfolane-nitrile and sulfolane-1-alkyne interactions in terms of DISQUAC

Abstract

Equilibrium temperatures for solid–liquid transitions of mixtures formed by sulfolane and ethanenitrile, propanenitrile, butanenitrile, or pentanenitrile were measured by a dynamic method. The solid–liquid equilibria phase diagrams show positive deviations from Raoult's law, except for the system with ethanenitrile, which is nearly ideal. The sulfolane–nitrile and sulfolane–1-alkyne interactions have been characterized in terms of the DISQUAC group contribution model. DISQUAC properly represents a complete set of thermodynamic properties: solid–liquid equilibria, molar excess enthalpies, and natural logarithms of activity coefficients. DISQUAC predictions are valid over a wide temperature range.Key words: solid–liquid equilibria, thermodynamics, mixtures, interactions.