Solubility Determination of 2-Phenyl-4 <i>H</i> -benzo[ <i>h</i> ]chromen-4-one in Mixed Solvents and Its Correlation with Thermodynamic Models

The solubility of 2-Phenyl-4H-benzo[h]chromen-4-one was measured in mixed solvents of ethyl acetate with n-propanol, n-butanol, or isobutanol using the isothermal saturation method at atmospheric pressure (101.3 kPa), across a temperature range of 278.15 to 318.15 K. Experimental data were well correlated by both the modified Apelblat model and the λh equation, with all correlation coefficients (R2) exceeding 0.99. According to the van’t Hoff equation, the apparent thermodynamic parameters (ΔsolH°, ΔsolS°, ΔsolG°) of the dissolution process were determined. Results demonstrate that the solubility of 2-Phenyl-4H-benzo[h]chromen-4-one increases significantly with temperature in all solvent systems studied. Furthermore, the positive values of ΔsolH°, ΔsolS°, and ΔsolG° indicate an endothermic, entropy-driven, and nonspontaneous dissolution process under the experimental conditions. These comprehensive findings provide essential guidance for optimizing the crystallization of 2-Phenyl-4H-benzo[h]chromen-4-one, facilitating the rational selection of solvent composition and operating temperature. This work also establishes a thermodynamic foundation for designing efficient antisolvent crystallization strategies.