•The solubility data of l-Theanine in different solvents were measured by using an equilibrium method.•Several models were used to correlate the experimental solubility data.•The mixing thermodynamic properties were calculated.The solubility data of l-Theanine in pure water and three kinds of water + organic solvent mxitures were measured in temperature ranges from (278.15 to 13.15) K by using an equilibrium method. The results show that the solubility of l-Theanine increases with the increasing of temperature in all selected solvents. The modified Apelblat equation and the λ-h model were applied to correlate the solubility data in pure water, while the modified Apelblat equation, the λ-h model, the NRTL model and the Jouyban–Acree model were applied to correlate the solubility data in binary solvent mixtures. Furthermore, the mixing thermodynamic properties of l-Theanine in different solvents were also calculated based on the NRTL model and experimental solubility data.

•The solubility data of pyraclostrobin in pure and binary solvents were determined and correlated.•The theory of solubility parameter was used to explain the cosolvency in binary solvents.•A modified mixing rule was proposed to calculate the solubility parameter of binary solvents.•The dissolution thermodynamic properties were calculated and discussed.The solubility of pyraclostrobin in five pure solvents and two binary solvent mixtures was measured from 283.15 K to 308.15 K using a static analytical method. Solubility in five pure solvents was well correlated by the modified Apelblat equation and Wilson model. While the CNIBS/R–K model was applied to correlate the solubility in two binary solvent mixtures, the correlation showed good agreement with experimental results. The solubility of pyraclostrobin reaches its maximum value at a certain cyclohexane mole fraction in the two binary solvent mixtures. The solubility parameter of pyraclostrobin was calculated by the Fedors method and a new modified mixing rule with preferable applicability was proposed to determine the solubility parameter of solvents. Then the co-solvency in the binary solvent mixtures can be explained based on the obtained solubility parameters. In a addition, the dissolution thermodynamic properties were calculated from the experimental values using the Wilson model.

•Solubility of 2-Cyano-4′-methylbiphenyl in eight pure solvents were determined by using UV spectrometer method.•The experimental solubility data of 2-Cyano-4′-methylbiphenyl were correlated and analyzed by three thermodynamic models.•Mixing thermodynamic properties of 2-Cyano-4′-methylbiphenyl were calculated and discussed.Solid–liquid equilibrium data of 2-Cyano-4′-methylbiphenyl (OTBN) are essential for the design and optimization of its production process. In this work, the solubility data of OTBN in pure solvents including 2-propanol, (R)-(−)-2-butanol (2-butanol, for short), methyl acetate, ethyl acetate, propyl acetate, butyl acetate, acetone and acetonitrile were determined in different temperature ranges from (268.05 to 303.25) K by using UV spectrometer method under atmospheric pressure. It was found that the order of OTBN solubility in these selected pure solvents at given temperature is acetone > methyl acetate > ethyl acetate > propyl acetate > butyl acetate > 2-butanol > 2-propanol and methyl acetate > acetonitrile > 2-butanol. In the temperature range investigated, the solubility data of OTBN increase with the increasing of temperature in all eight solvents. Furthermore, the modified Apelblat equation, the Wilson model and the NRTL model were applied to correlate the experimental solubility data. The correlated results are consistent with the experimental results. Finally, the mixing thermodynamic properties of OTBN in different solvents were calculated and analyzed based on the experimental solubility data and the Wilson model.

•The solubility of 4-aminobutyric acid in mono-solvents and binary solvent mixtures were experimentally determined.•The solubility data in five mono-solvents were correlated by three models.•Four models were employed to correlate solubility data in methanol + water binary solvent mixtures.•Solution mixing thermodynamics were calculated and the dissolution process were discussed.A laser monitoring dynamic method was used to determine the solubility of 4-aminobutyric acid in five mono-solvents of methanol, formamide, 1,2-propanediol, 1,3-propanediol and water, and (methanol + water) binary solvent mixtures over the temperature ranging from 283.15 K to 323.15 K at atmospheric pressure. It turns out to be that in different mono-solvents, the solubility of 4-aminobutyric acid is temperature dependent and increases with the increasing temperature. While in (methanol + water) binary solvent mixtures, the solubility is positively correlated with temperature and negatively correlated with the mole fraction of methanol. The modified Apelblat equation, λh equation and NRTL_Binary model were employed to correlate the solubility data in five mono-solvents. While in (methanol + water) binary solvent mixtures, the NRTL_Ternary model, CNIBS/R-K model and Jouyban-Acree models were applied. It is found that the correlated results are in good agreement with the experimental results. Furthermore, with the activity coefficients considered, solution mixing thermodynamics were calculated and the dissolution process of 4-aminobutyric acid is also discussed.

The densities and viscosities of electronic grade phosphoric acid (EGPA) aqueous solutions with the mass fraction of H3PO4 in the range of (78.7 to 90.2) % and temperatures from (283.15 to 313.15) K were measured. The densities range from (1.606 to 1.758) g·cm−3 with the mass fraction in the range of (78.7 to 90.2) % under experimental temperature. The viscosities range from (14.63 to 134.56) mPa·s with the mass fraction in the range of (78.7 to 90.2) % under experimental temperature. It is found that the measured densities and viscosities are well-correlated with the temperature and mass fraction of H3PO4 and are fitted to the regression equations. The thermal conductivities of EGPA coarse crystal (mixture of H3PO4·0.5H2O crystal and phosphoric acid aqueous solution) with the initial mass fraction of H3PO4 in the range of (84.2 to 90) % and temperatures from (280.15 to 298.15) K were measured by the cooling rate of 2 K·h−1 with a total cooling of (3 to 4) K under the initial temperature, which simulated the operation curve in industrial application. The result shows that the thermal conductivity under this condition increases obviously when the temperature rises. The thermal conductivity decreases when the initial mass fraction of H3PO4 increases.

The solubility of cefuroxime acid in four pure solvents and three binary solvents formed by water + acetone, ethanol + acetone, and 2-propanol + acetone at atmospheric pressure has been measured via a laser monitoring observation technique over the temperature range from (278.5 to 313.4) K. The solubility of cefuroxime acid increased with increasing temperature in water, 2-propanol, and ethanol but decreased in acetone. The heat flux measurements by a Differential Scanning Calorimeter (DSC) and solubility with temperature behavior were consistent. The solubility data of cefuroxime acid in pure solvents were correlated by the modified Apelblat equation, and the maximum average absolute error (AAE) was 0.07. The solubility data of cefuroxime acid in binary solvents at various temperatures were fitted by the Jouyban−Acree model, and the maximum AAE was 0.06. The solubility of cefuroxime acid in binary solvents was significantly higher than that in pure solvents and showed a maximum at a specific volume fraction of acetone.