Dissolution Equilibrium Of Myo-inosital And L-citrulline In Binary Solvent Mixtures

The solid solubility data not only are foundation of researching the solid-liquid theory but also provide basic physical data for industrial crystallization process and chemical process design and development. Future study on solid solubility was becoming very important, as food culture and health care were noted by more and more people, which provided theoretical support for the industrialization and food industry and so on.The solubility of the myo-inosital and the L-citrulline in water- ethanol solvent system was measured at different temperatures at atmospheric pressure using the gravimetric method. The experimental data were well-correlated by the modified Apelblat equation, the simplified CNIBS/R-K model and the 3D Jouyban-Acree model. The results show that, compared with other models, the 3D Jouyban-Acree model is more suitable in determining the solubility of the myo-inosital and the L-citrulline. On the basis of experimental data, thermodynamic properties, such as Gibbs energy(ΔG), enthalpy(ΔH), and entropy(ΔS)were calculated by the van’t Hoff equation. The values show that the dissolution of the myo-inosital and the L-citrulline was an endothermic, entropy-driven and non-spontaneous process, and the large value of the dissolution enthalpy shows that the solubility is most affected by temperature.In this paper, the dissolution behavior of the myo-inosital and the L-citrulline was analyzed and the results indicated that the viscosity was the key factor at low water content, and the polarity became the prior one as the polarity increased with the increase of water content. The crystal form of the myo-inosital is dihydrate form in pure water, while it is anhydrous form in pure ethanol. The dissolution process of the δ form of the L-citrulline did not occur crystal transform in water- ethanol solvent system, and δ form may be the most stable form.