Investigation on the solvent and temperature effect of climbazole solubility

The thermodynamic behavior of objective compounds plays an important role in crystallization and purification. In this work, the solubility of climbazole in nine pure solvents at (288.15-318.15 K) and in a water-ethanol mixed solution at (278.15-313.15 K) was determined by a gravimetric method. It was found that the solubility is positively related to temperature and ethanol content. Three well-known thermodynamic models (modified Apelblat equation, NRTL equation, lambda h equation) were used to correlate the experimental data, and the modified Apelblat equation showed better correlation results. Meanwhile, the thermodynamic properties of climbazole in selected solvents were investigated, and it was found that the dissolution process of climbazole is spontaneous, endothermic and entropy driven. Furthermore, the solvent effect was evaluated and discussed by Kamlet and Taft linear solvation energy relationship model (KAT-LSER) and Hansen solubility parameters (HSPs). The solvent-solvent interactions and the nonspecific dipolarity/polarizability interactions have a great influence on solubility. Additionally, the molecular surface characteristics and intermolecular interactions were studied by molecular simulation to reveal the molecular mechanism behind the solubility behavior of climbazole.