Determination and modelling of troxerutin solubility in eleven mono-solvents and (1,4-dioxane + 2-propanol) binary solvents at temperatures from 288.15 K to 323.15 K

In this work, a UV spectroscopic method was used to determine the solubility of troxerutin in eleven mono-solvents and (1,4-dioxane + 2-propanol) mixtures at different temperatures from 288.15 K to 323.15 K. The solubility of troxerutin was positively correlated with temperature in all selected solvents, and it showed a maximum value when the mole fraction of 2-propanol was 0.4 in binary solvent mixtures. The modified Apelblat equation, λh equation, CNIB/R-K model, NRTL model and Jouyban-Acree model were used to correlate the solubility data of troxerutin. It turned out that all the selected thermodynamic models could fit the results well, especially for the modified Apelblat equation with all the ARD values are less than 2%. Furthermore, the thermodynamic properties of troxerutin in different pure and binary solvents were also calculated and are discussed. The results indicated that the dissolution process of troxerutin in the experimental solvents was endothermic. Through analysis of enthalpy-entropy compensation in (1,4-dioxane + 2-propanol) mixtures, a non-linear ΔdHo versus ΔdHo plot was obtained, indicating that the driving mechanism changes with the proportion of 2-propanol in the dissolution process of troxerutin.