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

The solubility of 2-Phenyl-4 H -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 λ h equation, with all correlation coefficients ( R 2 ) exceeding 0.99. According to the van’t Hoff equation, the apparent thermodynamic parameters (Δ sol H °, Δ sol S °, Δ sol G °) of the dissolution process were determined. Results demonstrate that the solubility of 2-Phenyl-4 H -benzo[ h ]chromen-4-one increases significantly with temperature in all solvent systems studied. Furthermore, the positive values of Δ sol H °, Δ sol S °, and Δ sol G ° 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-4 H -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.