Oiling out and solubility measurement, molecular simulation and thermodynamic properties of d-tagatose in four aqueous binary solvent systems at 283.15 to 323.15 K

• Published in: The Journal of chemical thermodynamics 2025-02, Vol.201, p.107407, Article 107407
• Main Authors: Zou, Yuan, Luo, Jiaqi, Zhai, Xinyue, Wang, Yingchen, Zhang, Qiutong, Yan, Wenhao, Shi, Chuncheng, Su, Qifan, Yu, Qiushuo
• Format: Article
• Language: English
• Subjects: D-Tagatose solubility; Molecular dynamic simulation; Thermodynamic properties
• ISSN: 0021-9614
• DOI: 10.1016/j.jct.2024.107407

•Solubility of D-Tagatose in four binary solvents was determined using the anti-solvent assisted gravimetric method.•The experimental data was correlated with four thermodynamic models.•Molecular dynamic (MD) simulation was employed to explain the solubility behavior.•The dissolution of D-Tagatose was a non-spontaneous, endothermic and entropy-driven process. Solubility of D-Tagatose in four aqueous binary solvent systems from 278.15 K to 323.15 K was determined using the anti-solvent assisted gravimetric method. The solubility increases with temperature in all four binary solvents, with water, a good solvent, exhibiting a similar trend. In addition, the dissolution process generally follows the ’like dissolves like’ rule. The study indicates that the oiling out occurs when water exhibits a high molar fraction in water + 1-propanol, and water + isopropanol. Furthermore, we study the charge of the molecule using the molecular electrostatic potential surface (MEPS), aiming to analyze the molecular interactions. Then, to explain the dissolution behaviors of D-tagatose, the radial distribution function (RDF) by molecular dynamics simulations (MD) revealed a strong correlation between solute–solvent interactions and solubility, with significant solvent–solvent interactions. The solubility data was correlated using the modified Apelblat equation, Van’t Hoff equation, λh equation, and Jouyban-Acree model, with demonstrating the high consistency in the data. Finally, the thermodynamic properties revealed that the dissolution process of D-Tagatose is endothermic, and entropy-driven based on all positive values for ΔsolHo, ΔsolSo, ΔsolGo.