Thermodynamic study of the solubility of 2,4′-dihydroxydiphenyl sulfone in nine organic solvents from T = (278.15 to 313.15) K and thermodynamic properties of dissolution

• Solubility of 2,4′-dihydroxydiphenyl sulfone in nine pure solvents were determined.
• The solubility were correlated by using four thermodynamic models.
• The standard molar dissolution enthalpy and excess enthalpy of solution were calculated.

The solubility of 2,4′-dihydroxydiphenyl sulfone in methanol, ethanol, acetone, acetonitrile, ethyl acetate, 1,4-dioxane, n-butanol, isopropanol and 2-butanone was determined at temperatures from (278.15 to 313.15) K under 101.2 kPa by using the high-performance liquid chromatography (HPLC). With the increase in temperature, the solubility of 2,4′-dihydroxydiphenyl sulfone in these solvents increased. Generally, the mass fraction solubility followed the sequence from high to low in different solvents except for 1,4-dioxane: acetone > methanol > (2-butanone, ethanol) > isopropanol > n-butanol > ethyl acetate > acetonitrile. The solubility of 2,4′-dihydroxydiphenyl sulfone in 1,4-dioxane showed the strongest positive dependency on temperature. The measured solubility of 2,4′-dihydroxydiphenyl sulfone were correlated by using four thermodynamic models, which corresponded to the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of RMSD and RAD were 9.52 × 10−4 and 1.54%, respectively. By comparing the four models, the computed solubility using the modified Apelblat equation provided better agreement with the experimental values than those using the other three models. On the whole, the four models were all acceptable for describing the solubility of 2,4′-dihydroxydiphenyl sulfone in the selected solvents. In addition, the standard molar dissolution enthalpy and excess enthalpy of solution of 2,4′-dihydroxydiphenyl sulfone in the solvents were evaluated. The dissolution process of 2,4′-dihydroxydiphenyl sulfone in the selected solvents was endothermic. The study on the solubility of 2,4′-dihydroxydiphenyl sulfone in the selected solvents and solution properties can provide fundamental data in the separating process of 2,4′-dihydroxydiphenyl sulfone from its isomeric mixtures.

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