Determination and Correlation of the Solubility of Acetylpyrazine in Pure Solvents and Binary Solvent Mixtures

The solubilities of acetylpyrazine in seven pure solvents and one binary solvent mixture were determined by a dynamic analytic method at temperatures ranging from 268.15 to 308.15 K under atmospheric pressure. For pure solvents, the solubility of acetylpyrazine increases with increasing temperature and solvent polarity. For the binary solvent mixture of ethyl acetate and isopropanol, the solubility increases with increasing temperature and mole fraction of ethyl acetate. The solubility data were correlated with some thermodynamic models, including the modified Apelblat model, lambda h model, CNIBS/R-K model, and NRTL model. In addition, the relationship between solubility and solvent polarity was investigated by using the Arrhenius equation. All the models or equations gave satisfactory correlation results. The results showed that the solubility of acetylpyrazine generally rises with the increase of solvent polarity at the same temperature. Moreover, the dissolution thermodynamic properties of acetylpyrazine in different solvents were calculated and are discussed based on the NRTL model.