Thermodynamics of ternary mixtures containing sugars. SLE of D-fructose in pure and mixed solvents. Comparison between modified UNIQUAC and modified UNIFAC

New experimental data on the solubilities of D-fructose in the mixed solvents water/ethanol, water/methanol, and ethanol/methanol at 25, 40, and 60 degreesC are presented. These data were obtained using a standard, simple, and accurate experimental technique. Therefore, the database generated in our laboratory throughout a 4-year project now contains 205 solubility data points for systems with D-glucose, sucrose, and D-fructose in pure water, ethanol, and methanol and their mixtures. All of these data were correlated using the modified UNIQUAC, the entropic free-volume, and the original Flory-Huggins models, and the new parameters are given. The modified UNIQUAC model is the more accurate for the representation of the data. At the same time, predictions obtained with two different UNIFAC methods are compared.