LAUSR

Abstract In this work, the solubility of 4-methylphthalic anhydride in eight organic solvents (methyl acetate, acetone, acetonitrile, toluene, butyl acetate, carbon tetrachloride, cyclohexane, n-heptane) was studied experimentally by the isothermal saturation method at temperatures from (278.15 to 318.15) K under atmosphere pressure. Results show that the solubility of 4-methylphthalic anhydride in selected organic solvents increases with rising of temperature. Molecular simulation between solute and solvent was applied to reveal the solubility behavior based on density functional theory (DFT). The experimental data were correlated by five thermodynamic models including Van't Hoff equation, modified Apelblat equation, λh equation, NRTL and Wilson model. All the models give acceptable results in regression analysis of the solubility data. The modified Apelblat equation provides a better correlation in this study. The mixing thermodynamic properties including Gibbs energy, enthalpy and entropy of 4-methylphthalic anhydride in selected solvents were also obtained. Outcome shows that the dissolution of 4-methylphthalic anhydride in selected solvents is spontaneous and entropy-driven. This study can provide fundamental data for the separating of 4-methylphthalic anhydride.