Systematic study on solubility of chrysin in different organic solvents: The synergistic effect of multiple intermolecular interactions on the dissolution process

Abstract

The solubility of chrysin in N, N-dimethylformamide (DMF), acetone, ethyl acetate (EA), n-butanol, isopropanol, n-propanol, ethanol, methanol, n-hexane, and water was measured by using the static equilibrium method or the dynamic method at temperatures ranging from 293.2 to 333.2 K. Chrysin shows the easiest solvation in the dipolar aprotic solvents, followed by the polar protic solvents (alcohols), and shows poor solvation in the apolar aprotic solvents (hexane) and the strong polar water. The solubility of chrysin increases with rising temperature. The inherent microscopic solvation mechanisms were investigated qualitatively and quantitatively using a combination of the KAT-LSER model as well as σ-profile theory and molecular interaction energies calculated by COSMO–RS model. The results show the solvation process of chrysin in the different solvents is a complex process which depends on the synergistic effects of multiple molecular interactions between the solute and solvent together with the solvent and solvent. Moreover, the experimental solubility data in all solvents could be reasonably correlated by the modified Apelblat equation, λh equation, van't Hoff equation, Wilson model, and NRTL model, whereas the NRTL model and the modified Apelblat equation showed the most satisfactory fitting results. The dissolution thermodynamic properties, including enthalpy, entropy and Gibbs energy of chrysin in the dissolution process were evaluated using the van't Hoff equation. Moreover, the overall dissolution trend and the temperature-dependence of experimental solubility of chrysin in the different classes of solvents can be predicted correctly by the COSMO–RS model.