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| The solubilities of ginsenoside compound K in pure solvents and binary mixture solvents were determined at several temperatures from 278.15 K to 318.15 K by a static analytical method. The experimental solubility data in pure solvents were correlated by the van't Hoff plot, modified Apelblat equation, λh (Buchowski) equation, Wilson model and NRTL model, with the Wilson model giving the best correlation results. Based on the Wilson model and experimental data, the mixing Gibbs free energies, enthalpies and entropies of solutions and activity coefficients in pure solvents were predicted, and other thermodynamic properties (infinite-dilution activity coefficients and excess enthalpies) were calculated as well. In addition, the solubility was maximal at a certain water mole fraction in acetone + water mixture and acetonitrile + water mixture, whereas in methanol + water system, the solubility decreases with the water concentration increases monotonically. The solubilities in mixture solvents were correlated by the components of solvent using Wilson model. The partial molar Gibbs free energies with negative values were obtained, which indicates the changing of the solubility. |
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| Keywords:industry crystallization; ginsenoside; solubilities; Wilson model and NRTL model |
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