Thermodynamic Models for Determination of the Solubility of the (1:1) Complex of (Urea + l-Malic Acid) in (Methanol + Acetonitrile) Binary Solvent Mixtures

In this paper, we focused on solubility and solution thermodynamics of urea l-malic acid (1:1 solid state compound). By gravimetric method, the solubility of urea l-malic acid was measured in (methanol + acetonitrile) binary solvent mixtures in the temperature (from 278.15 K to 333.15 K). The solubility data were fitted using modified Apelblat model, a variant of the combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) model and Jouyban-Acree equation. Computational results showed that the modified Apelblat model has advantages than the other two models. In addition, we used van't Hoff analysis and Gibbs equation to help later scholars understand the thermodynamic properties in the process of dissolving. The experimental data showed that acetonitrile could be used as effective antisolvents.