Comparison of various cosolvency models for calculating solute solubility in water-cosolvent mixtures

Previously published cosolvency models are critically evaluated in terms of their ability to mathematically correlate solute solubility in binary solv ent mixtures as a function of solvent composition. Computational results sh ow that the accuracy of the models is improved by increasing the number of curve-fit parameters. However, the curve-fit parameters of several models a re limited. The combined nearly ideal binary solvent/Redlich-Kister, CNIBS/ R-K, was found to be the best solution model in terms of its ability to des cribe the experimental solubility in mixed solvents. Also presented is an e xtension of the mixture response surface model. The extension was found to improve the correlational ability of the original model. (C) 1999 Elsevier Science B.V. All rights reserved.