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In this study, the solubility of L-histidine in three different binary solvents, including (water + acetone), (water + ethanol) and (water + 2-propanol), was measured over temperatures from 283.15 K to 318.15 K by employing a gravimetric method at atmospheric pressure. It was found that the solubility of L-histidine in the binary mixed solvents increases with the increasing temperature at a given solvent composition, whereas it decreases with the rise of mole fraction of organic solvents. The experimental results were well correlated by the modified Apelblat equation, CNIBS/R-K model, combined version of the Jouyban-Acree model and NRTL model, respectively. This shows that these models can correlate the solubility in three binary mixed solvents accurately. Furthermore, the mixing thermodynamic properties of L-histidine in different binary solvent mixtures were also calculated based on the NRTL model. The result indicates that the mixing process of L-histidine is endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

The solubility of Avermectin B 1a (AVM B 1a ) in the three binary solvent mixtures, (acetone + water), (acetone + n-hexane) and (isopropanol + n-hexane) was determined gravimetrically with the temperature ranging from 283.15 K to 313.15 K under atmospheric conditions. The experimental results indicate that the solubility of AVM B 1a increased with increasing temperature at certain solvent composition, and decreased with increasing mole fraction of water and n-hexane. Besides, the modified Apelblat equation, CNIBS/R-K model and Jouyban-Acree model were employed to correlate the solubility results obtained. All the selected models provide satisfactory results. Furthermore, the mixing thermodynamic properties were calculated based on the NRTL equation, a binary activity coefficient model. We also calculated the thermodynamic properties of the dissolution process of AVM B 1a . The calculated results indicate that the dissolution process of AVM B 1a in the tested solvents is endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

The solubility of boscalid in five pure solvents, including methanol, ethanol, isopropanol, ethyl acetate and n-propyl acetate, and two binary solvent mixtures, including (ethanol + ethyl acetate) and (isopropanol + ethyl acetate), was determined by a gravimetric method with temperatures ranging from (288.15 to 313.15) K. It turns out that the solubility of boscalid increases with the increasing of temperature in all selected solvents. Moreover, it is interesting that the solubility of boscalid in the two binary solvent mixtures performed a maximum effect with the decreasing mole fraction of ethyl acetate at a given temperature. The solubility of boscalid in pure solvents was correlated by the modified Apelblat model and λh model while that in binary solvent mixtures was correlated by the modified Apelblat model, CNIBS/R-K model and Jouyban-Acree model. It is found that all the models could give satisfactory correlation results with less than 3% of all the ARD values. Furthermore, the thermodynamic properties of the mixing processes in all solvents selected were calculated and discussed based on the NRTL model. [ABSTRACT FROM AUTHOR]

In this work, a UV spectroscopic method was used to determine the solubility of troxerutin in eleven mono-solvents and (1,4-dioxane + 2-propanol) mixtures at different temperatures from 288.15 K to 323.15 K. The solubility of troxerutin was positively correlated with temperature in all selected solvents, and it showed a maximum value when the mole fraction of 2-propanol was 0.4 in binary solvent mixtures. The modified Apelblat equation, λh equation, CNIB/R-K model, NRTL model and Jouyban-Acree model were used to correlate the solubility data of troxerutin. It turned out that all the selected thermodynamic models could fit the results well, especially for the modified Apelblat equation with all the ARD values are less than 2%. Furthermore, the thermodynamic properties of troxerutin in different pure and binary solvents were also calculated and are discussed. The results indicated that the dissolution process of troxerutin in the experimental solvents was endothermic. Through analysis of enthalpy-entropy compensation in (1,4-dioxane + 2-propanol) mixtures, a non-linear Δ d H o versus Δ d H o plot was obtained, indicating that the driving mechanism changes with the proportion of 2-propanol in the dissolution process of troxerutin. [ABSTRACT FROM AUTHOR]