Experimental Determination and Model Prediction of Solid Solubility of Multifunctional Compounds in Pure and Mixed Nonelectrolyte Solvents

We seek an improved methodology for the design of solvents and solvent mixtures for separations, especially purification of solids by crystallization. This paper reports new data for the solubility of four multifunctional solids: 3-nitrophthalimide, 5-fluoroisatin, 2-amino-5-nitrobenzophenone, and benzimidazole. The heat of fusion for each solid was measured along with the solubility in several pure and mixed solvents at 283, 298, and 313 K. These data were used to determine new parameters for the MOSCED model for these solids, and those parameters were then used to predict the solid solubility in mixed solvents. The ability to use thermodynamic models to predict solubility of complex solutes provides a new paradigm for the selection of both pure and mixed solvents.