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Liquid − liquid equilibrium (LLE) data for the water + 2,3-butanediol (2,3-BD) + solvent (n-hexanol or iso-pentanol) ternary systems were obtained at different temperatures (298.2, 308.2, and 318.2 K) under 101.3 kPa. Distribution coefficients and separation factors were calculated accordingly. Distribution coefficients and separation factors were greater than 0.2 and 2.5, respectively, for both n-hexanol and iso-pentanol, which indicated that they were feasible to extract 2,3-BD from aqueous solution. Meanwhile, the reliability of the experimental LLE data was confirmed by both Othmer − Tobias equation and Hand equation. Lastly, the LLE data were correlated by both thermodynamic nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models, and their binary interaction parameters were correlated from the data. In addition, topological analysis related to the Gibbs minor common tangent test was applied to validate the binary interaction parameters. Supplemental data for this article is available online at here. [ABSTRACT FROM AUTHOR]

The solubility data of N-acetyl-L-glutamine in aqueous solution with different proportions of methanol and ethanol were determined with a static analytical method from 293.15 to 318.15 K. The data were then correlated by five models including the modified Apelblat equation, Van't Hoff equation, local composition model (NRTL model), CNIBS/Redlich-Kister model, and Jouyban-Acree model. The results show that Van't Hoff equation agrees well with the experimental data. When the ratio of methanol or ethanol in aqueous solution is in the range of 0.2-0.4, the solubility of N-acetyl-L-glutamine reaches its maximum. Besides, the melting temperature and fusion enthalpy of N-acetyl-L-glutamine were measured by the differential scanning calorimetry (DSC) and no polymorphism was found in the systems studied. The thermodynamic properties including enthalpy, entropy and Gibbs free energy during dissolution were calculated accordingly in this work. [ABSTRACT FROM AUTHOR]

AbstractThe solubility of nicotinohydrazide in two binary solvents were determined by a static weight method from 293.15 to 318.15 K. It found that the solubility of nicotinohydrazide was influenced by temperature, solvent polarity, and solvent composition. Meanwhile, the TG-DSC analysis was used to obtain the weight change and thermal effect of nicotinohydrazide. The XRD analysis indicated that the crystal morphology of nicotinohydrazide was coincident in five different solvents. Furthermore, the models including modified Apelblat equation, Van’t Hoff equation, Jouyban-Acree model, and CNIBS/R-K model were used to fit the experimental data. It was concluded that the four models were reliable in fitting the experimental data. Then the dissolution apparent thermodynamic was obtained, which explained well the dissolution of nicotinohydrazide. This study could help optimize and control the industrial crystallization of nicotinohydrazide. [ABSTRACT FROM AUTHOR]

AbstractGlycylglycine (Gly–Gly) is a crucial biochemical reagent widely used in cosmetics, food additives, and medicine. Using the equilibrium method, the solubility data of Gly–Gly in four binary solvents (ethanol/isopropanol/ethanediol/acetone + water) were investigated at temperatures over a range of 288.15–328.15 K under 101.3 kPa, as well as in the binary solvent of acetic acid + water from 293.15 to 333.15 K. The solubility data were correlated by Apelblat-Jouyban Acree, Van’t Hoff-Jouyban Acree, and CNIBS/Redlich-Kister models. Additionally, the radial distribution function was obtained through molecular dynamic simulation. It presented the unusual dissolution behavior of Gly–Gly in acetic acid and water mixture. The apparent thermodynamic properties, including standard enthalpy, Gibbs free energy, and entropy change of dissolution, were obtained accordingly. This article could help the industrial crystallization of Gly–Gly. [ABSTRACT FROM AUTHOR]