The solid–liquid equilibrium for thiamphenicol in 13 neat solvents (ethanol, methanol, n-propanol, isopropyl alcohol, n-butanol, acetone, acetonitrile, ethyl acetate, 2-butanone, toluene, water, N,N-dimethylformamide, and 1,4-dioxane) was built with the static method at temperatures T = (278.15 to 318.15) K under pressure of 101.2 kPa, and the thiamphenicol solubilities in the selected solvents were measured by using high-performance liquid chromatography. Generally, the solubility data in mole fraction in the selected solvents ranked as N,N-dimethylformamide > acetone > methanol >1,4-dioxane >2-butanone > ethanol > acetonitrile > ethyl acetate > n-propanol > isopropyl alcohol > water > n-butanol > toluene. The nonrandom two-liquid model, Wilson model, modified Apelblat equation, and λh equation were employed to describe the solubility behavior of thiamphenicol in theses solvents. The maximum values of the RMSD and RAD were 4.08 × 10–4 and 2.02%, respectively, and the correlation results by using the modified Apelblat equation were best among the studied models. Additionally, the mixing properties, activity coefficient at infinitesimal concentration and reduced excess enthalpy were derived.

The isobaric vapor–liquid equilibrium data for binary systems of 1,3,5-trichlorobenzene (1) + 3,5-dichloroaniline (2) and 3-chloroaniline (1) + 3,5-dichloroaniline (2) were measured experimentally under pressures of 20.00, 60.00 and 101.20 kPa using an inclined ebulliometer. Thermodynamic consistency of the vapor–liquid equilibrium data was tested by means of the Herington semiempirical method, and the isobaric vapor–liquid equilibrium data were correlated with three activity coefficient models, which were Wilson, NRTL and UNIQUAC. The energy interaction parameters were acquired by a nonlinear least-squares regression method for the three thermodynamic models. Results indicate that all the three activity coefficient models can describe the measured isobaric vapor–liquid data acceptably. The isobaric vapor–liquid equilibrium data determined in the present work are important in the design and operation for purification of 3,5-dichloroaniline by distillation.

The preferential solvation parameters (δx1,3) of Boscalid in solvent mixtures of ethanol (1) + ethyl acetate (2), and isopropanol (1) + ethyl acetate (2) were derived from their available solubility data by means of the inverse Kirkwood–Buff integrals method. The values of δx1,3 vary non-linearly with the solvent (1) proportion in the two solvent mixtures. For the ethanol (1) + ethyl acetate (2) system, the values of δx1,3 are negative in ethanol-rich and ethyl acetate-rich mixtures, but positive in intermediate compositions; for the isopropanol (1) + ethyl acetate (2) system, the values of δx1,3 are positive in ethyl acetate-rich mixtures and in intermediate compositions, but negative in isopropanol-rich mixtures. The δx1,3 values are positive indicating that Boscalid is preferentially solvated by ethyl acetate. The magnitude of the preferential solvation of Boscalid by ethyl acetate is higher in isopropanol (1) + ethyl acetate (2) mixtures than in ethanol (1) + ethyl acetate (2) mixtures at 298.15, 308.15 and 313.15 K. The ethyl acetate action may be related to the disordered structure of ethanol or isopropanol molecules around the polar moieties of Boscalid, which increases the solvation, with maximum values near x1 = 0.40–0.45 for the two solvent mixtures.

•Solubility of 4-nitrobenzaldehyde in eleven solvents were determined.•The solubility was correlated with four thermodynamic models.•Mixing properties of the solutions were computed based on Wilson model.In this work, the solubility of 4-nitrobenzaldehyde in methanol, ethanol, isopropanol, n-butanol, acetone, ethyl acetate, acetonitrile, 2-butanone, N,N-dimethylformamide, n-propanol and toluene was determined with the isothermal saturation method at the temperatures ranging from (273.15 to 313.15) K under atmosphere pressure. The mole fraction solubility increased with increasing temperature and obeyed the following order from high to low in the selected solvents except for acetonitrile: N,N-dimethylformamide > acetone > 2-butanone > ethyl acetate > methanol > toluene > ethanol > n-propanol > n-butanol > isopropanol. The results correlated with four models, which corresponded to the Apelblat equation, λh equation, Wilson model and NRTL model. The largest value of root-mean-square deviation (RMSD) was 11.53 × 10−4, and relative average deviation (RAD  ), 2.36%. The four thermodynamic models could all be employed to correlate the mole fraction solubility of 4-nitrobenzaldehyde in the selected solvents under studied conditions. In addition, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were computed. The mixing process of 4-nitrobenzaldehyde in the solvents was spontaneous and endothermic. The acquired solubility and thermodynamic studies would be very helpful for optimizing the purification process and further study of 4-nitrobenzaldehyde.

•Solubility of 3-nitrobenzaldehyde in twelve solvents were determined.•The solubility were correlated with four thermodynamic models.•Mixing properties of the solutions were computed based on NRTL model.The solubility was measured for 3-nitrobenzaldehyde in methanol, ethanol, isopropanol, n-butanol, acetonitrile, acetone, ethyl acetate, toluene, N,N-dimethylformamide, acetic acid, cyclohexane and n-propanol by using a high-performance liquid chromatography analysis under pressure of 101.2 kPa. The temperatures of solubility determination were from (273.15 to 303.15) K. The mole fraction solubility of 3-nitrobenzaldehyde increased with the increase in temperature, and obeyed the following order from high to low in different solvents: N,N-dimethylformamide > (acetone, acetonitrile) > ethyl acetate > toluene > methanol > acetic acid > ethanol > n-propanol > n-butanol > isopropanol > cyclohexane. Four models, modified Apelblat equation, λh equation, Wilson model and NRTL model were employed to correlate the experimental mole fraction solubility. The largest root-mean-square deviation (RMSD) was 6.98 × 10−3, and the largest relative average deviation (RAD  ) was 1.93% for each set of solubility results. On the whole, the calculated solubility values were in good agreement with the experimental results for the four selected models, and the NRTL provided the best results. Moreover, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were computed based on the NRTL model. The experimental solubility, thermodynamic models and thermodynamic properties are very important in the purification process of isomeric mixtures of nitrobenzaldehydes.

•Preferential solvation of pioglitazone hydrochloride in four binary solvent mixtures was discussed.•Preferential solvation parameters were derived by IKBI method.•Preferential solvation magnitude is highest in ethanol + water and lowest in isopropanol + water.•Pioglitazone hydrochloride is preferentially solvated by cosolvent in intermediate compositions.The preferential solvation parameters (δx1,3) of pioglitazone hydrochloride in four binary solvent mixtures of {ethanol (1) + water (2)}, {N-methyl pyrrolidone (NMP) (1) + water (2)}, {propylene glycol (1) + water (2)} and {N,N-dimethylsulfoxide (DMSO) (1) + water (2)} were derived from their available solubility data by means of the inverse Kirkwood–Buff integrals method. The values of δx1,3 vary non-linearly with the co-solvent (1) proportion in all the aqueous mixtures. The preferential solvation magnitude of pioglitazone hydrochloride by the co-solvent is highest in {ethanol (1) + water (2)} mixtures and lowest in {propylene glycol (1) + water (2)}. For the systems of (ethanol + water) and (NMP + water), the values of δx1,3 are negative in water-rich mixtures and co-solvent-rich mixtures, but positive in intermediate compositions. However, for the {propylene glycol (1) + water (2)} and {DMSO (1) + water (2)} mixtures with composition 0.20 < x1 < 1, the δx1,3 values are positive indicating that pioglitazone hydrochloride is preferentially solvated by co-solvent. The positive δx1,3 values could be explained based on the higher acidic behaviour of pioglitazone hydrochloride molecules interacting with the hydrogen acceptor groups present in co-solvent.Download high-res image (114KB)Download full-size image

•Solubility of ribavirin (II) in co-solvent + water were determined and correlated.•Apparent dissolution enthalpy was computed.•Preferential solvation parameters were obtained by Inverse Kirkwood–Buff integrals.•Ribavirin (II) was preferentially solvated by water in intermediate composition and co-solvent-rich mixtures.The equilibrium solubility of ribavirin in solvent mixtures of {methanol (1) + water (2)}, {n-propanol (1) + water (2)}, {acetonitrile (1) + water (2)} and {1,4-dioxane (1) + water (2)} was determined experimentally by using isothermal dissolution equilibrium method within the temperature range from (278.15 to 318.15) K under atmospheric pressure (101.1 kPa). At the same temperature and mass fraction of methanol (n-propanol, acetonitrile or 1,4-dioxane), the mole fraction solubility of ribavirin is greater in (methanol + water) than in the other three solvent mixtures. The preferential solvation parameters were derived from their thermodynamic solution properties by means of the inverse Kirkwood–Buff integrals. The preferential solvation parameters for methanol, n-propanol, acetonitrile or 1,4-dioxane (δx1,3) were negative in the four solvent mixtures with a very wide compositions, which indicated that ribavirin was preferentially solvated by water. Temperature had little effect on the preferential solvation magnitudes. The higher solvation by water could be explained in terms of the higher acidic behaviour of water interacting with the Lewis basic groups of the ribavirin. Besides, the solubility of the drugs was mathematically represented by using the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model obtaining average relative deviations lower than 1.57% for correlative studies. It is noteworthy that the solubility data presented in this work contribute to expansion of the physicochemical information about the solubility of drugs in binary solvent mixtures and also allows the thermodynamic analysis of the respective dissolution and specific solvation process.Download high-res image (265KB)Download full-size image

•Solubilities of 4-methyl-2-nitroaniline in fourteen solvents were determined.•Solubility data were correlated by using four thermodynamic models.•Mixing properties of solutions were calculated.The knowledge of solubility and solution thermodynamics for 4-methyl-2-nitroaniline in different solvents is essential for its preparation, purification and further theoretical studies. In this work, the solid-liquid equilibrium for 4-methyl-2-nitroaniline in fourteen organic solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, toluene, ethyl acetate, acetonitrile, 2-butanone, 1,4-dioxane, N,N-dimethylformamide, carbon tetrachloride, 1,2-dichloroethane and chlorobenzene) was built with the isothermal saturation method at temperatures T = (278.15–318.15) K under pressure of 101.2 kPa, and the solubility values of 4-methyl-2-nitroaniline in these solvents were determined by a high-performance liquid chromatography (HPLC). Generally, the mole fraction solubilities obeyed the following order from high to low in different solvents: 2-butanone > N,N-dimethylformamide > ethyl acetate > 1,4-dioxane > (acetonitrile, 1,2-dichloroethane) > chlorobenzene > (toluene, n-butanol) > n-propanol > isopropanol > ethanol > methanol > carbon tetrachloride. The obtained solubility data of 4-methyl-2-nitroaniline in the selected solvents were correlated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. Results showed that the largest values of relative average deviation and root-mean-square deviation acquired with the four models were no greater than 1.03% and 6.89 × 10−4, respectively. The modified Apelblat equation provided better correlation results than the other three models. Moreover, the mixing properties, including mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration and reduced excess enthalpy were computed. The mixing process of 4-methyl-2-nitroaniline in the studied solvents was spontaneous and endothermic. The obtained solubility and thermodynamic studies would be very helpful for optimizing the preparation and purification process of 4-methyl-2-nitroaniline.Download high-res image (227KB)Download full-size image

Solubilities of hymecromone in neat solvents of N,N-dimethylformamide (DMF), methanol, ethanol and n-propanol, and their binary mixed solvents of DMF + methanol, DMF + ethanol and DMF + n-propanol were determined using an isothermal dissolution equilibrium method within the temperature range from 278.15 K to 313.15 K under 101.1 kPa. They were correlated with the Jouyban–Acree, van't Hoff–Jouyban–Acree and Apelblat–Jouyban–Acree models obtaining relative average deviations (RAD) lower than 0.51% and root-mean-square deviation (RMSD) lower than 4.42 × 10−4. Positive values of the dissolution enthalpy illustrated that the dissolution process of hymecromone in these mixed solvents was endothermic. Furthermore, the preferential solvation parameters were derived by using the inverse Kirkwood–Buff integrals. The preferential solvation parameters (δx1,3) were negative in alcohol-rich mixtures but positive in compositions from 0.35 (0.43, 0.50) in the mole fraction of DMF to neat DMF.

•Solubility of 2-methyl-6-nitroaniline in four binary mixed solvents were determined.•Solubility data were correlated and calculated by six models.•The standard dissolution enthalpy for the dissolution processes were computed.The solubility of 2-methyl-6-nitroaniline in binary mixed solvents of (ethyl acetate + methanol), (ethyl acetate + ethanol), (ethyl acetate + n-propanol) and (ethyl acetate + isopropanol) was determined experimentally by using the isothermal dissolution method within the temperature range from (278.15–313.15) K under atmosphere pressure. The solubility of 2-methyl-6-nitroaniline increased with increasing temperature and mass fraction of ethyl acetate in each binary system. At the same temperature and mass fraction of ethyl acetate, the mole fraction solubility of 2-methyl-6-nitroaniline was greater in (ethyl acetate + n-propanol) than in the other three mixed solvents. The achieved solubility values were correlated by employing Jouyban-Acree model, van’t Hoff-Jouyban-Acree model, Apelblat-Jouyban-Acree model, Ma model, Sun model and CNIBS/R-K model. The values of relative average deviations (RAD) and root-mean-square deviations (RMSD) were no greater than 1.79% and 20.56 × 10−4 for the six models. In general, the Jouyban-Acree model proved to provide better representation of the experimental solubility. Furthermore, the dissolution enthalpies of the dissolution process were calculated. Positive values of dissolution enthalpy showed that the dissolution process of 2-methyl-6-nitroaniline in these mixed solvents was endothermic. The experimental solubility results and models presented in the present work are essential in the practical process for production and purification of 2-methyl-6-nitroaniline.

•The solubility of 3,5-dinitrobenzoic acid in acetone was determined.•Solubility of m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone was determined.•Three ternary phase diagrams were constructed for the ternary system.•The ternary phase diagrams were calculated by Wilson model and NRTL model.The solubility of 3,5-dinitrobenzoic acid in acetone at the temperatures ranging from (283.15 to 318.15) K and the mutual solubility of the ternary m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone system at (283.15, 298.15 and 313.15) K were determined experimentally by using the isothermal saturation method under atmosphere pressure (101.2 kPa). Three isothermal ternary phase diagrams were constructed according to the measured mutual solubility data. In each ternary phase diagram, there was one co-saturated point, two boundary curves, and three crystalline regions. The modified Apelblat equation, λh equation, NRTL model and Wilson model were used to correlate the solubility of 3,5-dinitrobenzoic acid in acetone; and the NRTL and Wilson models, the mutual solubility for the ternary m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone system. The value of root-mean-square deviation (RMSD) was 8.53 × 10−4 for the binary system of 3,5-dinitrobenzoic acid + acetone; and the largest value of RMSD was 81.08 × 10−4 for the ternary system.

•Solubility of paclobutrazol in nine pure organic solvents were determined.•The solubility were correlated by using four thermodynamic models.•The mixing properties of solution were computed in terms of Wilson model.The mole fraction solubility of paclobutrazol ((R,R) and (S,S)) mixture in nine pure solvents including ethanol, isopropanol, n-propanol, 1-butanol, ethyl acetate, toluene, acetone, acetonitrile and 1,4-dioxane was determined experimentally by using the isothermal saturation method over a temperature range from (278.15 to 318.15) K under atmospheric pressure. The mole fraction solubility of paclobutrazol in the selected solvents increased with a rise of temperature. In general, at a certain temperature, they decreased according to the following order in different solvents except for ethyl acetate: toluene > 1,4-dioxane > acetone > 1-butanol > n-propanol > ethanol > isopropanol > acetonitrile. The paclobutrazol solubility showed stronger dependency on temperature in ethyl acetate than in the other solvents. The solubility determined for paclobutrazol in the selected solvents was correlated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 3.98 × 10−4 and 1.53%, respectively. On the whole, the four thermodynamic models were all acceptable for describing the systems of paclobutrazol in these solvents. Furthermore, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were obtained. The mixing process of paclobutrazol was spontaneous and exothermic in the solvents studied. The solubility determined and the thermodynamic properties derived should be very helpful for optimizing the purification process of paclobutrazol.

•Solubilities of 3-amino-1,2,4-triazole in ten organic solvents were determined.•The solubilities were correlated by using four thermodynamic models.•The mixing properties of solution were computed in terms of Wilson model.The solubility of 3-amino-1,2,4-triazole in ten organic solvents including ethanol, isopropanol, n-propanol, methanol, ethyl acetate, acetone, acetonitrile, 1,4-dioxane, N-methyl-2-pyrrolidone and 2-butanone was determined experimentally by the isothermal saturation method over a temperature range from T = 283.15 K to T = 318.15 K under 101.1 kPa. For the studied temperature range, the solubility of 3-amino-1,2,4-triazole in mole fraction in the solvents increased with a rise of temperature. On the whole, they obeyed the following order from high to low in different solvents: N-methyl-2-pyrrolidone > methanol > ethanol > n-propanol > (isopropanol, acetone) > 1,4-dioxane > 2-butanone > (ethyl acetate, acetonitrile). The determined solubility results of 3-amino-1,2,4-triazole in the solvents studied were correlated using the modified Apelblat equation, Buchowski–Ksiazaczak λh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 9.45 × 10−4 and 2.16%, respectively. In general, the four thermodynamic models were all acceptable for describing the solubility behaviour of 3-amino-1,2,4-triazole in these solvents. Furthermore, the mixing properties including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were acquired. The solution process of 3-amino-1,2,4-triazole was spontaneous and favourable in the selected solvents. The solubility values obtained and the thermodynamic studies would be very useful for optimizing the purification process of 3-amino-1,2,4-triazole.

•Solubility for quaternary system of adipic acid + succinic acid + glutaric acid + ethanol were determined.•The quaternary phase diagrams were constructed at three temperatures according to the Jãneck method.•The quaternary solid-liquid phase equilibrium was calculated by Wilson and NRTL models.Solid-liquid phase equilibrium and solubility for the quaternary system of (adipic acid + succinic acid + glutaric acid + ethanol) at (283.15, 303.15, and 313.15) K were determined by using an isothermal saturation method under atmosphere pressure (101.2 kPa). Based on the determined mutual solubility, the quaternary phase diagrams were constructed at the studied temperatures according to the Jãneck method. At each temperature, the quaternary phase diagram included three crystallization regions of pure solid, three co-saturated curves and one eutectic point. The three pure solids corresponded to pure adipic acid, pure succinic acid and pure glutaric acid, which were confirmed by Schreinemaker’s method of wet residue and X-ray powder diffraction. At the same temperature, the crystallization regions of succinic acid and adipic acid are larger than that of glutaric acid. Furthermore, the quaternary solid-liquid phase equilibrium was calculated by using the Wilson and NRTL models. The calculated quaternary phase diagrams agreed well with experimental results. The values of RMSD were 2.46 and 1.08 for Wilson model and NRTL model, respectively. The solid-liquid equilibrium phase diagrams and the thermodynamic models for the quaternary system could provide the fundamental basis for the separation process of a specific dibasic acid from its mixtures via solvent crystallization.Download high-res image (90KB)Download full-size image

The solubilities of 4-(methylsulfonyl)benzaldehyde in the binary mixed solvents acetonitrile + methanol, acetonitrile + ethanol and acetonitrile + isopropanol were determined experimentally using an isothermal dissolution equilibrium method within the temperature range from 283.15 to 318.15 K under atmospheric pressure. The solubility of 4-(methylsulfonyl)benzaldehyde increased with increasing temperature and mass fraction of acetonitrile in each binary system. At the same temperature and mass fraction of acetonitrile, the mole fraction solubility of 4-(methylsulfonyl)benzaldehyde is greater in (acetonitrile + methanol) than in the other two mixed solvents. The solubility data were correlated using the CNIBS/R-K model, Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, Apelblat–Jouyban–Acree model, Ma model and Sun model. The maximum values of relative average deviation (RAD) and root-mean-square deviation (RMSD) are 1.53% and 1.17 × 10−4, respectively. All of the selected models provided good representation of the experimental solubilities. Furthermore, the standard enthalpies of dissolution were calculated. The dissolution process for 4-(methylsulfonyl)benzaldehyde in these mixed solvents is endothermic. The experimental solubility and the models presented in this work are important for the production and purification of 4-(methylsulfonyl)benzaldehyde.

•SLE for 4-nitrobenzaldehyde + 3-nitrobenzaldehyde + ethyl acetate system was determined.•The ternary phase diagrams were constructed at 278.15 K, 288.15 K and 298.15 K.•The phase diagrams were correlated and calculated by Wilson and NRTL models.In this work, the solid-liquid phase equilibrium data for ternary system of 4-nitrobenzaldehyde + 3-nitrobenzaldehyde + ethyl acetate were determined by using an isothermal saturation method at three temperatures of 278.15 K, 288.15 K, and 298.15 K under atmosphere pressure (101.2 kPa). Three isothermal phase diagrams were built based on the measured solubility data. There were two pure solids formed in the ternary system at a certain temperature, which corresponded to pure 3-nitrobenzaldehyde and pure 4-nitrobenzaldehyde, and were confirmed by Schreinemaker's method of wet residue and X-ray powder diffraction. The crystallization region of 4-nitrobenzaldehyde was larger than that of 3-nitrobenzaldehyde at each temperature. Two thermodynamic models, NRTL and Wilson were employed to correlate and calculate the mutual solubility data for the system of 4-nitrobenzaldehyde + 3-nitrobenzaldehyde + ethyl acetate. The largest value of RMSD for the ternary system was 5.95 × 10− 3, and the maximum value of RAD was 3.02%. The calculated results with NRTL model agreed well than those with Wilson model. The solid-liquid equilibrium phase diagrams and the thermodynamic models for the ternary system can provide the foundation for separating high purity3-nitrobenzaldehyde or 4-nitrobenzaldehyde from its isomeric mixtures.Download high-res image (130KB)Download full-size image

•Preferential solvation of rosmarinic acid in methanol/ethanol + water was discussed.•Preferential solvation parameters were derived by IKBI method.•Rosmarinic acid is preferentially solvated by water in water-rich mixtures.•Rosmarinic acid is preferentially solvated by methanol/ethanol in methanol/ethanol-rich mixtures.The preferential solvation parameters (δx1,3) of rosmarinic acid in binary solvent mixtures of ethanol + water and methanol + water were derived from their thermodynamic properties by means of the inverse Kirkwood–Buff integrals method. δx1,3 was negative in water-rich mixtures but positive in solvent compositions from 0.20 or 0.24 to 1 in mole fraction of methanol or ethanol, respectively. It was conjecturable that in water-rich mixtures, the hydrophobic hydration around the nonpolar aromatic groups of rosmarinic acid played a relevant role in the solvation. The higher solvation by methanol or ethanol in mixtures of similar co-solvent compositions could be mainly due to polarity effects. The preference of rosmarinic acid in intermediate compositions and in methanol-rich or ethanol-rich mixtures could be explained in terms of the higher acidic behavior of rosmarinic acid molecules interacting with the hydrogen acceptor groups in methanol or ethanol. The calculations were required in the pharmaceutical and chemical industries to save time and money in the optimization of the solubilization and/or crystallization process designs.Download high-res image (147KB)Download full-size image

•Solubility of 3-nitrobenzaldehyde in DMF + ethanol/n-propanol/n-butanol were determined.•Preferential solvation parameters were obtained by IKBI method.•3-Nitrobenzaldehyde was preferentially solvated by DMF in DMF-rich mixtures.The solubility of 3-nitrobenzaldehyde in mixed solvents of N,N-dimethylformamide + ethanol, N,N-dimethylformamide + n-propanol and N,N-dimethylformamide + n-butanol were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (273.15 to 298.15) K under 101.2 kPa. The mole fraction solubility of 3-nitrobenzaldehyde increased with increasing temperature and mass fraction of the N,N-dimethylformamide (DMF). At the same temperature and mass fraction of DMF, the mole fraction solubility of 3-nitrobenzaldehyde in ethanol was greater than those in the other two systems. The obtained solubilities were correlated by employing Jouyban-Acree, van't Hoff-Jouyban-Acree and Apelblat-Jouyban-Acree models. The largest value of RAD was 0.30 × 10− 2, and of RMSD, 8.10 × 10− 4. Dissolution of 3-nitrobenzaldehyde in these mixed solvents was an endothermic process. Preferential solvation parameters of 3-nitrobenzaldehyde were also derived by means of the inverse Kirkwood-Buff integrals method. The preferential solvation parameter δx1,3 was negative in ethanol, n-propanol or n-butanol-rich mixtures but positive in DMF-rich mixtures. The solubility data presented in this work expand the physicochemical information about 3-nitrobenzaldehyde in binary solvent mixtures.Download high-res image (319KB)Download full-size image

•Solubilities of 5-amino-3-methyl-1-phenylpyrazole in ten pure solvents were determined.•The solubility data were correlated with four solubility models.•The mixing properties were calculated.•A rough estimate of solute–solvent intermolecular interactions was made.With the isothermal dissolution equilibrium method, the solid-liquid phase equilibrium for 5-amino-3-methyl-1-phenylpyrazole in ten organic solvents including methanol, ethanol, n-propanol, isopropanol, 2-butanone, acetonitrile, n-butanol, toluene, 1,4-dioxane and isobutanol was established over a temperature range from (283.15 to 318.15) K at atmospheric pressure (101.1 kPa), and the solubility of 5-amino-3-methyl-1-phenylpyrazole in these solvents were determined by a high-performance liquid chromatography (HPLC). The mole fraction solubility of 5-amino-3-methyl-1-phenylpyrazole in the solvents increased with increasing temperature within the temperature range studied, and obeyed the following sequence from high to low in different solvents: 1,4-dioxane > acetonitrile > methanol > isobutanol > ethanol > n-propanol > isopropanol > 2-butanone > toluene > cyclohexane. The obtained solubility values of 5-amino-3-methyl-1-phenylpyrazole were correlated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 4.95 × 10− 4 and 0.62%, respectively. In total, the four thermodynamic models were all acceptable for describing the solubility behavior of 5-amino-3-methyl-1-phenylpyrazole in these solvents. Furthermore, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration and reduced excess enthalpy were obtained with Wilson model. The results demonstrated that the dissolution process of 5-amino-3-methyl-1-phenylpyrazole was spontaneous and favorable in the ten organic solvents. Moreover, the solute–solvent intermolecular interaction was roughly estimated based on the values of activity coefficients. The determined solubility data and thermodynamic models in this work would be helpful to optimize the purification procedure of 5-amino-3-methyl-1-phenylpyrazole.Download high-res image (183KB)Download full-size image

•Solubility of 4-nitrobenzaldehyde solubility in three binary mixed solvents were determined.•Solubility data were correlated and computed by five models.•Standard dissolution enthalpy for the dissolution processes were evaluated.The solubility of 4-nitrobenzaldehyde in mixed solvents of (N,N-dimethylformamide + ethanol), (N,N-dimethylformamide + n-propanol) and (N,N-dimethylformamide + n-butanol) were determined experimentally by using the isothermal dissolution method within the temperatures ranging from (273.15 to 313.15) K under atmosphere pressure (101.2 kPa). The solubility of 4-nitrobenzaldehyde increased with increasing temperature and mass fraction of N,N-dimethylformamide for the binary systems of (N,N-dimethylformamide + ethanol), (N,N-dimethylformamide + n-propanol) and (N,N-dimethylformamide + n-butanol). At the same temperature and mass fraction of N,N-dimethylformamide, the mole fraction solubility of 4-nitrobenzaldehyde in ethanol was greater than those in the other two systems. The obtained solubility data were correlated by employing CNIBS/R-K model, Jouyban–Acree model, van't Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree and Sun model. The largest values of relative average deviation (RAD) and root-mean-square deviation (RMSD) between the experimental and calculated solubility were 0.92 × 10− 2 and 6.22 × 10− 4, respectively, which were obtained with Jouyban–Acree model for the system of N,N-dimethylformamide + n-propanol. On the whole, the CNIBS/R-K model was proven to provide better representation of the experimental solubility data. Based on the measured solubility, the dissolution enthalpies of the dissolution process were computed. Dissolution process of 4-nitrobenzaldehyde in these mixed solvents was endothermic. The experimental solubility and solubility models could be helpful in purifying 4-nitrobenzaldehyde from its isomeric mixtures.Download high-res image (215KB)Download full-size image

•Solubilities of 2-mercaptobenzothiazole in eleven solvents were determined.•Solubility data were correlated by using four thermodynamic models.•Mixing properties of solutions were calculated.The solid-liquid equilibrium of 2-mercaptobenzothiazole in eleven solvents of methanol, n-propanol, i-propanol, n-butanol, i-butanol, acetonitrile, ethyl acetate, toluene, 2-butanone, chloroform and 1,4-dioxane was investigated by the isothermal dissolution equilibrium method under atmosphere pressure of 101.2 kPa, and the solubilities were determined by a high-performance liquid chromatography at T = (273.15, 275.65, 278.15, 280.65, 283.15, 285.65, 288.15, 290.65, 293.15, 295.65, 298.15, 300.65, 303.15, 305.65, 308.15, 310.65, 313.15, 315.65 and 318.15) K. For the eleven solvents, the mole fraction solubility of 2-mercaptobenzothiazole increased with increasing temperature. Thee obeyed the following order from high to low in different solvents: 2-butanone > 1,4-dioxane > ethyl acetate > n-butanol > n-propanol > i-butanol > i-Propanol > methanol > chloroform > acetonitrile > toluene. The solubility values obtained for 2-mercaptobenzothiazole in the selected solvents were correlated with four models, which corresponded to modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of relative average deviation and the root-mean-square deviation acquired with the four models were 0.59 % and 4.86 × 10−4, respectively. Generally, the four thermodynamic models were all acceptable for describing the solubility behaviour of 2-mercaptobenzothiazole in the solvents. In addition, based on the Wilson model, the mixing thermodynamic properties (mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration and reduced excess enthalpy) of solutions were derived. The results indicated that the dissolution of 2-mercaptobenzothiazole in all studied cases was spontaneous and favourable. The solubility values and thermodynamic relations of 2-mercaptobenzothiazole in selected solvents would be invoked as fundamental data and models regarding the purification process of 2-mercaptobenzothiazole.Download high-res image (232KB)Download full-size image

•Solubility of paclobutrazol in ethanol/n-propanol/1,4-dioxane + water were determined.•Preferential solvation parameters were obtained by IKBI method.•Preferential solvation magnitude is highest in ethanol + water mixtures.•Preferential was preferentially solvated by cosolvent in intermediate composition and cosolvent-rich mixtures.The equilibrium solubility of paclobutrazol in co-solvent mixtures of ethanol (1) + water (2), n-propanol (1) + water (2) and 1,4-dioxane (1) + water (2) were determined experimentally by using isothermal dissolution equilibrium method within the temperature range from (278.15 to 313.15) K under atmospheric pressure (101.1 kPa). At the same temperature and mass fraction of co-solvent, the mole fraction solubility of paclobutrazol in the three binary co-solvent mixtures obeyed the following order from high to low: 1,4-dioxane (1) + water (2) > n-propanol (1) + water (2) > ethanol (1) + water (2). The preferential solvation parameters were derived from their thermodynamic solution properties by means of the inverse Kirkwood–Buff integrals. The preferential solvation parameters for ethanol, n-propanol or 1,4-dioxane (δx1,3) were negative in water-rich mixtures but positive in compositions from 0.24 (0.19, 0.18) in mole fraction of ethanol (n-propanol or 1,4-dioxane) to pure ethanol (n-propanol or 1,4-dioxane). The preferential solvation magnitude of paclobutrazol by the co-solvent was highest in ethanol (1) + water (2) mixtures and lowest in n-propanol (1) + water (2). It was conjecturable that in the former case hydrophobic hydration around the aromatic rings played the main role in the drug’s solvation. The higher solvation by ethanol (n-propanol or 1,4-dioxane) in intermediate compositions and in colsolvent-rich mixtures could be explained in terms of the higher basic behaviour of this co-solvent interacting with the Lewis acidic groups of the paclobutrazol. Besides, the drugs’ solubilities were mathematically represented by using the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model obtaining average relative deviations lower than 4.73% for correlative studies.Download high-res image (251KB)Download full-size image

•Solubility of econazole nitrate in methanol/ethanol/1,4-dioxane + water were determined.•Preferential solvation parameters were derived by IKBI method.•Econazole nitrate was preferentially solvated by alcohol in intermediate composition and alcohol-rich mixtures.•Econazole nitrate is preferentially solvated by cosolvent in intermediate composition for 1,4-dioxane mixtures.The solubility of econazole nitrate in binary mixed solvents of (methanol + water, ethanol + water and 1,4-dioxane + water) were measured experimentally via the isothermal dissolution equilibrium method in the temperature range of (278.15–318.15) K under 101.2 kPa. For the (1,4-dioxane + water) system, at a certain composition of 1,4-dioxane, the solubility of econazole nitrate increased with an increase in temperature; nevertheless at the same temperature, they increased at first and then decreased with an increase in mass fraction of 1,4-dioxane. At the same temperature and mass fraction of methanol, ethanol or 1,4-dioxane, the solubility of econazole nitrate was greater in (methanol + water) than in the other two mixed solvents. The solubility values were correlated by using Jouyban-Acree model, and the dissolution enthalpies of the dissolution process were computed. Preferential solvation parameters of econazole nitrate were also derived by means of the inverse Kirkwood-Buff integrals method. The preferential solvation parameter by water δx1,3 is negative in water-rich mixtures but positive in compositions from 0.31 to 1.0 in mole fraction of methanol and from 0.24 to 1.0 in mole fraction of ethanol. It is conjecturable that in intermediate composition of alcohol and alcohol-rich mixtures the interaction by acidic hydrogen-bonding by methanol/ethanol on the basic sites of econazole nitrate played a relevant role in the drug solvation. However in 1,4-dioxane (1) + water (2) mixtures with 0.18 < x1 < 0.50 positive δx1,3 values were observed, but with 0.50 < x1 < 1.0 negative δx1,3 values were observed again. The solubility data presented in this work expand the physicochemical information about drugs in binary aqueous-co-solvent mixtures.Download high-res image (221KB)Download full-size image

•Preferential solvation of dehydroepiandrosterone acetate in cosolvent + ethyl acetate mixtures was studied.•Preferential solvation parameters were obtained by IKBI method.•DHEA acetate is preferentially solvated by ethyl acetate in ethyl acetate-rich mixtures.•The preferential solvation parameter is greater than zero in ethyl acetate-rich mixtures.The preferential solvation parameters (δx1,3) of dehydroepiandrosterone acetate (DHEA acetate) in three co-solvent mixtures of methanol (1) + ethyl acetate (2), ethanol (1) + ethyl acetate (2), and isopropanol (1) + ethyl acetate (2) were derived from their available solubility data by means of the inverse Kirkwood–Buff integrals method. The values of δx1,3 vary non-linearly with the co-solvent (1) proportion in all the co-solvent mixtures. For the studied systems, the values of δx1,3 are negative in alcohol-rich mixtures, but positive in ethyl acetate-rich mixtures. The preferential solvation magnitude of DHEA acetate by the ethyl acetate is highest in {methanol (1) + ethyl acetate (2)} mixtures at 293.15 K and 303.15 K. While at 313.15 K, it is highest in {isopropanol (1) + ethyl acetate (2)} mixtures. The δx1,3 values are positive indicating that DHEA acetate is preferentially solvated by ethyl acetate. The co-solvent action may be related to the disordered structure of ethyl acetate molecules around the non-polar moieties of DHEA acetate which increases the solvation having maximum values near to x1 = 0.25–0.35 for the three co-solvent mixtures.Download high-res image (135KB)Download full-size image

•Solubilities of 3-nitro-o-toluic acid in nine organic solvents were determined.•The solubilities were correlated by using four thermodynamic models.•The mixing properties of solution were computed based on Wilson model.Separation of 3-nitro-o-toluic acid from its isomeric mixtures has essential significance in industry. In this work, by using isothermal saturation method, the solid-liquid equilibrium for 3-nitro-o-toluic acid in nine organic solvents (acetonitrile, methanol, ethanol, n-propanol, isopropanol, ethyl acetate, acetone, 1,4-dioxane and 2-butanone) were obtained experimentally within a temperature range from (283.15 to 318.15) K under atmosphere pressure of 101.2 kPa, and the solubility values of 3-nitro-o-toluic acid in these solvents were determined by a high-performance liquid chromatography. Within the studied temperature range, the mole fraction solubility of 3-nitro-o-toluic acid in selected organic solvents increased with increasing temperature. Except for ethyl acetate, the descending order of the mole fraction solubility values were as follow: 1,4-dioxane > acetone > 2-butanone > methanol > ethanol > isopropanol > n-propanol > acetonitrile. The solubility values determined for 3-nitro-o-toluic acid in the selected solvents were correlated and back calculated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of RAD and RMSD obtained with the four models were 0.67% and 4.02 × 10−4, respectively. In general, the four thermodynamic models were all acceptable for describing the solubility behaviour of 3-nitro-o-toluic acid in these solvents. In addition, the apparent mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration and reduced excess enthalpy were calculated. The acquired solubility data and thermodynamic studies would be very important in optimizing the separation process of 3-nitro-o-toluic acid from its isomeric mixtures.Download high-res image (185KB)Download full-size image

•Solubility of 5-phenyltetrazole in thirteen neat solvents were determined.•Solubility of 5-phenyltetrazole in (methanol + ethyl acetate) mixtures were measured.•Solubility data were correlated and calculated by using different models.•Preferential solvation in (methanol + ethyl acetate) were discussed.The solid-liquid phase equilibrium of 5-phenyltetrazole in thirteen mono-solvents including methanol, ethanol, n-propanol, isopropanol, acetone, 2-butanone, acetonitrile, ethyl acetate, toluene, 1,4-dioxane, cyclohexane, dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF) and liquid mixtures (methanol + ethyl acetate) were obtained experimentally via the isothermal saturation method within the temperatures from (283.15 to 318.15) K under about 101.2 kPa. It was intuitive to notice that the solubility values of 5-phenyltetrazole in studied solvents increased with increasing temperature. The descending order of the solubility data in different mono-solvents was as follows: DMSO > DMF > acetone > methanol > (ethanol, 2-butanone) > isopropanol > n-propanol > 1,4-dioxane > ethyl acetate > acetonitrile > toluene > cyclohexane. For the binary solvent mixtures of (methanol + ethyl acetate) with given initial compositions, the maximum solubility was observed in neat methanol. The solubility data in mono-solvents were correlated and calculated by using the modified Apelblat equation and the Buchowski-Książczak λh equation; and in the binary solvent mixtures, by three cosolvency models. The largest values of RAD and RMSD were 1.25% and 4.83 × 10−4, respectively. The apparent dissolution enthalpy was positive, illustrating that the dissolution process of 5-phenyltetrazole was endothermic. Finally, the preferential solvation parameters (δx1,3) of 5-phenyltetrazole in (methanol + ethyl acetate) mixtures at (293.15–313.15) K were derived by using the inverse Kirkwood–Buff integrals method. The δx1,3 values were positive in methanol-rich compositions and negative in the other regions.Download high-res image (148KB)Download full-size image

•Solubility of 2-methyl-4-nitroaniline in ethyl acetate + alcohol were determined and correlated.•Preferential solvation parameters were obtained by IKBI method.•2-Methyl-4-nitroaniline was preferentially solvated by alcohol in alcohol-rich mixtures.The mole fraction solubility of 2-methyl-4-nitroaniline in binary mixed solvents of (ethyl acetate + methanol), (ethyl acetate + ethanol), (ethyl acetate + n-propanol) and (ethyl acetate + isopropanol) was determined experimentally by using static method at temperatures from (278.15 to 313.15) K under atmospheric pressure. The solubility increased with increasing temperature and mass fraction of ethyl acetate. At the same temperature and mass fraction of ethyl acetate, the mole fraction solubility in (ethyl acetate + methanol) was greater than those in the other mixed solvents. The solubility values were correlated with Jouyban–Acree model, van’t Hoff-Jouyban-Acree model, modified Apelblat-Jouyban-Acree model, Ma model, and Sun model. The maximum values of relative average deviations and root-mean-square deviations were 0.47 × 10−2 and 2.26 × 10−4, respectively. Preferential solvation parameters of the solute were also derived by means of the inverse Kirkwood-Buff integrals (IKBI) method. The preferential solvation parameters δx1,3 are negative in alcohol-rich composition, but positive in intermediate and ethyl acetate-rich composition. The ethyl acetate action may be related to the breaking of the ordered structure of alcohol around the polar moieties of 2-methyl-4-nitroaniline. The positive δx1,3 values could be explained based on the higher acidic behaviour of 2-methyl-4-nitroaniline molecules interacting with the hydrogen acceptor groups present in ethyl acetate. This work expands the physicochemical information about solid in binary solvent mixtures.Download high-res image (233KB)Download full-size image

•Solubility of 4-bromopyrazole in methanol/ethanol + water were determined and correlated.•Apparent dissolution enthalpy was computed.•Preferential solvation parameters were obtained by IKBI method.•Preferential solvation magnitude is highest in ethanol + water mixtures.•4-Bromopyrazole was preferentially solvated by alcohol in intermediate composition and alcohol-rich mixtures.The solubility of 4-bromopyrazole in binary (methanol + water) and (ethanol + water) solvent mixtures were investigated by using the isothermal dissolution equilibrium method under atmosphere pressure. The maximum solubility was observed in neat methanol or ethanol. At the same mass fraction of methanol or ethanol and temperature, the solubility of 4-bromopyrazole was greater in (ethanol + water) than in (methanol + water) mixed solvents. The obtained solubility data were correlated with Jouyban-Acree model, modified Apelblat-Jouyban-Acree model and van’t Hoff-Jouyban-Acree model. The largest values of relative average deviation and the root-mean-square deviation were 3.59 × 10−2 and 6.60 × 10−3, respectively. Positive apparent enthalpies showed that dissolution of 4-bromopyrazole in these mixed solvents was an endothermic process. Preferential solvation parameters of 4-bromopyrazole were also derived by means of the inverse Kirkwood-Buff integrals method. The preferential solvation parameter was negative in water-rich mixtures but positive in intermediate composition and alcohol-rich mixtures. In the latter case, it is conjecturable that 4-bromopyrazole is acting as a Lewis acid with alcohol molecules. The co-solvent action may be related to the breaking of the ordered structure of water around the polar moieties of 4-bromopyrazole which increases the solvation of this solute. The solubility data and thermodynamic study expanded the physicochemical information about 4-bromopyrazole in binary solvent mixtures.Download high-res image (235KB)Download full-size image

•Preferential solvation of diazepam in five binary solvent mixtures was discussed.•Preferential solvation parameters were derived by IKBI method.•For ethanol (propylene glycol, NMP, 1,4-dioxane) + water, preferential solvation magnitude is highest in 1,4-dioxane + water.•The preferential solvation between in tert-butanol (1) + water (2) and in the other solvent mixtures is different.The preferential solvation parameters (δx1,3) of diazepam in binary solvent mixtures of {ethanol (1) + water (2)}, {propylene glycol (1) + water (2)}, {NMP (1) + water (2)} and {1,4-dioxane (1) + water (2)} at 298.2 K and {tert-butanol (1) + water (2)} at (299.2–313.2) K were derived from their available solubility values by using the inverse Kirkwood–Buff integrals method. The values of δx1,3 vary non-linearly with the co-solvent (1) proportion in all the aqueous mixtures. For the former four co-solvent mixtures, the preferential solvation magnitude of diazepam by the co-solvent is highest in {1,4-dioxane (1) + water (2)} mixtures and lowest in {ethanol (1) + water (2)} mixtures. For the former four systems, the values of δx1,3 are negative in water-rich mixtures, which indicates that diazepam could act as a Lewis base to establish hydrogen bonds with the proton-donor functional groups of the co-solvents (1) (with the exception of 1,4-dioxane). The same behaviour was also observed for ethanol (1) + water (2) mixtures with co-solvent-rich composition. In the {ethanol (1) + water (2)} mixtures with composition 0.241 < x1 < 0.688, {NMP (1) + water (2)} mixtures with composition 0.164 < x1 < 1.0, {propylene glycol (1) + water (2)} mixtures with composition 0.20 < x1 < 1.0 and {1,4-dioxane (1) + water (2)} mixtures with composition 0.175 < x1 < 1.0, diazepam is preferentially solvated by co-solvent. Some differences between the behaviours of diazepam in {tert-butanol (1) + water (2)} mixtures and the other four co-solvent mixtures were found.Download high-res image (195KB)Download full-size image

•Solubility of 2-methyl-4-nitroaniline in twelve solvents were determined.•The solubility data were correlated with four thermodynamic models.•The mixing properties of the solutions were obtained.The knowledge of solubility and solution thermodynamics for 2-methyl-4-nitroaniline in different solvents is essential for its purification and further theoretical studies. In this work, the solid-liquid equilibrium for 2-methyl-4-nitroaniline in eleven pure organic solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, toluene, ethyl acetate, acetonitrile, 2-butanone, acetone and cyclohexane) was established with the isothermal saturation method at temperatures T = (278.15–313.15) K under pressure of 101.2 kPa, and the solubility of 2-methyl-4-nitroaniline in these solvents were determined by a high-performance liquid chromatography (HPLC). In general, the mole fraction solubility obeyed the following order from high to low in different solvents: 2-butanone > acetone > ethyl acetate > acetonitrile > methanol > ethanol > n-propanol > n-butanol > isopropanol > toluene > cyclohexane. The modified Apelblat equation, λh equation, Wilson model and NRTL model were employed to correlate the measured solubility values of 2-methyl-4-nitroaniline in the selected solvents. Results show that the largest values of RAD and RMSD obtained with the four models are no greater than 0.71% and 3.27 × 10−4, respectively. The modified Apelblat equation provided better results than the other three models. Furthermore, the mixing properties, including Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were computed. The dissolution process of 2-methyl-4-nitroaniline is spontaneous and favourable in the selected solvents. The solubility and associated models would be very useful for optimizing the separation process of the isomeric mixtures of 2-methyl-4-nitroaniline and 2-methyl-6-nitroaniline.

•Solubility of cetilistat in four neat solvents were determined and correlated.•Preferential solvation parameters were obtained by IKBI method.•Preferential solvation magnitude is highest in acetonitrile + water mixtures.•Cetilistat was preferentially solvated by co-solvent in intermediate and co-solvent-rich mixtures.The solubility of cetilistat in neat solvents of acetone, isopropanol, acetonitrile and water were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (278.15 to 323.15) K under atmospheric pressure of 101.1 kPa. At the fixed temperature, the mole fraction solubility of cetilistat was greater in acetone than in the other three neat solvents. They ranked as acetone > isopropanol > acetonitrile > water. The obtained solubilities were correlated with Apelblat equation. The largest value of relative average deviation was 0.86 × 10− 2, and of root-mean-square deviation, 15.55 × 10− 4. Furthermore, the preferential solvation parameters (δx1,3) of cetilistat in co-solvent mixtures of acetone (1) + water (2), isopropanol (1) + water (2) and acetonitrile (1) + water (2) were derived from their thermodynamic properties by means of the inverse Kirkwood–Buff integrals method. The values of δx1,3 varied non-linearly with the co-solvent (1) proportion in all the aqueous mixtures. The preferential solvation parameter was negative in water-rich mixtures but positive in intermediate composition and co-solvent-rich mixtures. In the latter case, it was conjecturable that cetilistat was acting as a Lewis acid with co-solvent molecules. The co-solvent action might be related to the breaking of the ordered structure of water around the polar moieties of cetilistat which increased the solvation of this drug. The solubility data and thermodynamic study expanded the physicochemical information about cetilistat in binary solvent mixtures, which was required in the pharmaceutical and chemical industries to save time and money in the optimization of the solubilization and/or crystallization process designs.Download high-res image (242KB)Download full-size image

•Solubility of adenosine in four (co-solvent + water) mixtures were determined.•The solubility data were correlated by using three thermodynamic models.•Preferential solvation parameters were derived by IKBI method.•Adenosine was preferentially solvated by water in water-rich mixtures.The equilibrium solubility of adenosine in co-solvent mixtures of {(N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide and propylene glycol) + water} were determined experimentally by the isothermal dissolution equilibrium method in the temperature range of (278.15–323.15) K under atmospheric pressure of 101.0 kPa. The maximum solubility was observed in neat N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide or propylene glycol. The mole fraction solubility of adenosine increased with increasing temperature and mass fraction of co-solvent in each binary system. At the same temperature and mass fraction of the organic solvent, the solubility of adenosine was greater in (N-methyl-2-pyrrolidone + water) than in the other three mixed solvents. The Jouyban-Acree model, Van’t Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model were employed to correlate the measured solubility data. The largest values of relative average deviation and root-mean-square deviation were 4.87 × 10−2 and 3.52 × 10−4, respectively. Positive values of the dissolution enthalpy illustrated that the dissolution process of adenosine in these mixed solvents was endothermic. Moreover, the preferential solvation parameters were derived from their thermodynamic solution properties by using the inverse Kirkwood–Buff integrals. For the four co-solvent mixtures with intermediate composition and co-solvent-rich mixtures, adenosine is preferentially solvated neither by organic solvent nor by water. However, adenosine is preferentially solvated by water in water-rich mixtures. Adenosine could act mainly as a Lewis base interacting with acidic hydrogen atoms of water.Download high-res image (247KB)Download full-size image

•The solid–liquid phase equilibrium of adipic acid + glutaric acid + ethanol system were measured under 101.3 kPa.•The ternary phase diagrams were constructed at three temperatures.•The ternary phase diagrams were correlated and calculated by Wilson and NRTL model.•The densities of the equilibrium liquid phase were obtained and correlated with an empirical equation.In this work, the solid–liquid phase equilibrium data for ternary system of adipic acid + glutaric acid + ethanol were measured using an isothermal saturation method at the three temperatures of 283.15, 303.15, and 313.15 K under 101.3 kPa. Three isothermal phase diagrams were built according to the measured solubility data. There were two pure solids formed in the ternary system at a given temperature, which corresponded to pure adipic acid and pure glutaric acid, and were confirmed by Schreinemaker's method of wet residue. The crystallization region of glutaric acid was smaller than that of adipic acid at each temperature. Two thermodynamic models, NRTL and Wilson were employed to correlate and calculate the mutual solubility data for the ternary adipic acid + glutaric acid + ethanol system. Results indicated that calculated results with NRTL model agreed well than those with Wilson model. Furthermore, the densities of the equilibrium liquid phase were obtained and correlated with an empirical equation.

•Solid–liquid equilibrium formed by adipic acid, urea and diethylene glycol were determined.•The binary and ternary phase diagrams were constructed.•The phase diagrams were correlated and predicted using Wilson and NRTL model.•Densities of equilibrium liquore were obtained and correlated with an empirical equation.Solid–liquid phase equilibrium data for binary (adipic acid + diethylene glycol) and (urea + diethylene glycol) systems at temperatures from (298.15–333.15) K and ternary (adipic acid + urea + diethylene glycol) system at temperatures of 298.15 K, 313.15 K and 333.15 K were determined herein under pressure of 101.3 kPa. The corresponding solids formed in the ternary system were confirmed by Schreinemakers' method of wet residue. Three isothermal phase diagrams were constructed in terms of the measured mutual solubility data. Two pure solids were formed at each temperature, which corresponded to pure adipic acid and pure urea. The crystallization region of urea was smaller than that of adipic acid at each temperature. NRTL model and Wilson model were used to correlate the obtained solubility data, and the interaction parameters' values of adipic acid-urea were acquired. The calculated solubility with the two models agreed well with the experimental values.

•Solubility were determined for dehydroepiandrosterone acetate in nine solvents.•Solubility were correlated with four thermodynamic models.•Apparent standard enthalpy and excess enthalpy of solutions were evaluated.The solubility was measured for dehydroepiandrosterone acetate in cyclohexane, acetone, ethyl acetate, acetonitrile, methanol, 1-butanol, ethanol and isopropanol by high-performance liquid chromatography analysis under the pressure of 101.3 kPa. The temperature of the determination varied from (273.15 K to 318.15) K. The dehydroepiandrosterone acetate solubility increased with the increase in temperature, and obeyed the following order from high to low: ethyl acetate > acetone > 1-butanol > acetonitrile > (cyclohexane, isopropanol) > ethanol > methanol. They were correlated with four models, viz. the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest average standard deviation is 5.93 × 10−4, and the largest relative average deviation is 1.18% for each set of solubility values. The calculated solubility was in good agreement with the experimental values for the four models. Moreover, the thermodynamic properties of the solution process, including the apparent standard dissolution enthalpy and excess enthalpy were calculated. The experimental solubility, thermodynamic models and thermodynamic properties are very important in the purification process of dehydroepiandrosterone acetate.

•Solubility of 2-methyl-6-nitroaniline in ten solvents were determined.•The solubility were correlated with four thermodynamic models.•Standard dissolution enthalpy and excess enthalpy of the solutions were computed.Knowledge of solubility for 2-methyl-6-nitroaniline in different solvents is essential for its purification and further theoretical studies. In this paper, the solid-liquid equilibrium for 2-methyl-6-nitroaniline in ten pure organic solvents (methanol, ethanol, n-propanol, isopropanol, toluene, ethyl acetate, acetonitrile, acetone, cyclohexane and 1,4-dioxane) was established using the isothermal saturation method at temperatures T = (278.15–313.15)  K under pressure of 101.2 kPa, and the solubility of 2-methyl-6-nitroaniline in these solvents were determined by a high-performance liquid chromatography (HPLC). In general, the mole fraction solubility followed the following order from high to low in different solvents: 1,4-dioxane (0.1799–0.3390) > acetone (0.1128–0.3010) > ethyl acetate (0.08414–0.2654) > acetonitrile (0.04179–0.2027) > toluene (0.02367–0.1104) > n-propanol (0.01080–0.04514) > ethanol (0.01020–0.04202) > isopropanol (0.008595–0.03763) > methanol (0.007391–0.03198) > cyclohexane (0.001027–0.005617). The modified Apelblat equation, λh equation, Wilson model and NRTL model were employed to correlate the measured solubility data of 2-methyl-6-nitroaniline in the selected solvents. Results indicated that the largest values of RAD and RMSD acquired by the four models were less than 0.76% and 9.13 × 10−4, respectively. The modified Apelblat equation provided better results than the other three models. Furthermore, the standard dissolution enthalpy and excess enthalpy of the solutions were computed from the solubility values. The standard dissolution enthalpies vary within the range from (14.88 to 45.57) kJ·mol−1 and are all positive, the dissolution process of 2-methyl-6-nitroaniline is endothermic. The solubility data and models would be very useful for optimizing the separation process of the isomeric mixtures of 2-methyl-6-nitroaniline and 2-methyl-4-nitroaniline.

The binary solid–liquid phase equilibrium for 4-(methylsulfonyl)benzaldehyde in methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, acetonitrile, toluene, and acetic acid were studied experimentally within the temperatures range from (283.15 to 318.15) K under 101.3 kPa by using a static equilibrium method. With the increase in temperature, the solubility of 4-(methylsulfonyl)benzaldehyde in these solvents increased. The solubility values from high to low obeyed the following order in different solvents: acetone > acetonitrile > acetic acid > methanol > ethanol > toluene > 1-butanol > 1-propanol > 2-propanol. The modified Apelblat equation, λh equation, Wilson model, and nonrandom two liquid model were employed to correlate the experimental solubility of 4-(methylsulfonyl)benzaldehyde in the nine solvents. The calculated solubility with the modified Apelblat equation provided better agreement than those with the other three models. Generally, the regressed results by the four thermodynamic models could be acceptable for 4-(methylsulfonyl)benzaldehyde in the studied solvents. The acquired solubility data could provide a theoretical basis for the purification of crude 4-(methylsulfonyl)benzaldehyde.

•Solubility of ACET in nine organic solvents were determined at different temperatures.•The measured solubility data were correlated with five models.•The standard dissolution enthalpy and excess enthalpy were calculated.Knowledge of solubility for ethyl 5-amino-4-cyano-3-(2-ethoxy-2-oxoethyl)-2-thiophenecarboxylate (ACET) in different solvents is essential for its purification and further theoretical studies. In this paper, the solubility of ACET in selected pure solvents, including methanol, ethanol, 1-butanol, n-propanol, isopropanol, toluene, ethyl acetate, acetonitrile and acetone were acquired by a high-performance liquid chromatography (HPLC) at T = (273.15, 278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K under pressure of 0.1 MPa. Generally, they obeyed the following order from high to low in different solvents: acetone > ethyl acetate > acetonitrile > methanol > ethanol > isopropanol > n-propanol > 1-butanol > toluene. The obtained solubility data of ACET in selected solvents were correlated by the van’t Hoff equation, modified Apelblat equation, λhλh equation, Wilson model and NRTL model. The correlated values of the five equations agreed well with the experimental values and the Wilson model gives better correlation results than other models. Furthermore, the standard dissolution enthalpy and excess enthalpy for dissolution process of ACET were calculated from the experimental solubility by using the van’t Hoff equation. The solubility values of ACET in different solvents and thermodynamic relations would be invoked as fundamental data and models regarding the crystallization process of ACET.

•Solid-liquid equilibrium of 3,4/2,3-dichloronitrobenzene + methanol were determined.•The ternary phase diagrams were constructed at three temperatures.•The ternary phase diagrams were correlated and calculated by NRTL and Wilson model.The solid–liquid phase equilibrium for ternary system of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + methanol were determined experimentally by the method of isothermal solution saturation at temperatures of 283.15 K, 293.15 K and 303.15 K under pressure of 101.3 kPa. According to the obtained solubility data, the isothermal phase diagrams of the system were constructed. At each temperature, there were two pure solid phases formed, which were confirmed by Schreinemakers' wet residue method and corresponded to pure 3,4-dichloronitrobenzene and pure 2,3-dichloronitrobenzene. The crystallization regions of pure 3,4-dichloronitrobenzene and pure 2,3-dichloronitrobenzene increased with decreasing in temperature. The crystalline region of 2,3-dichloronitrobenzene was larger than that of 3,4-dichloronitrobenzene at the same temperature, and increased rapidly as the temperature increase. The data of solid–liquid phase equilibrium were correlated with NRTL model and Wilson model. The calculated solubility data with NRTL model agreed well with the experimental values. The mutual solubility data and ternary phase diagrams for the system were of great significance for optimizing the purification procedure of 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene.

•1-Methyl-4-(methylsulfonyl)benzene solubility in nine solvents were determined.•The solubility were correlated by using four thermodynamic models.•The mixing properties of solutions were calculated.The solid-liquid equilibrium for 1-methyl-4-(methylsulfonyl)benzene in nine solvents (methanol, ethanol, acetonitrile, ethyl acetate, acetone, N,N-dimethylformamide, n-butanol, n-propanol, isopropanol) were determined at temperatures from 278.15 K to 318.15 K by using the isothermal saturation method under atmosphere pressure, and the solubility of 1-methyl-4-(methylsulfonyl)benzene in the solvents were analysed by the high-performance liquid chromatography (HPLC). On the whole, the solubility obeyed the following order from high to low for the selected solvents: N,N-dimethylformamide > acetone > acetonitrile > ethyl acetate > methanol > ethanol > n-propanol > n-butanol > isopropanol. The four thermodynamic models, modified Apelblat equation, λh equation, Wilson model and NRTL model were used to describe the solubility results obtained. The largest values of relative average deviation (RAD) and root-mean-square deviations (RMSD) were 1.48% and 56.85 × 10−4, respectively. The calculated solubility with the four models agreed well with the experimental values. Furthermore, the mixing properties, including mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were calculated for the dissolution process of 1-methyl-4-(methylsulfonyl)benzene in these solvents. The mixing process of 1-methyl-4-(methylsulfonyl)benzene was spontaneous and favourable in the selected solvents. The solubility of 1-methyl-4-(methylsulfonyl)benzene in different solvents and thermodynamic relations would be invoked as basic data and models for the purification process of 1-methyl-4-(methylsulfonyl)benzene.

The density, viscosity, and refractive index of aqueous solutions of sodium lactobionate were measured as a function of molality m = 0.0251, 0.0502, 0.0753, 0.100, 0.126, 0.151, 0.176, and 0.201 mol·kg–1 and temperature T = 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K. They all increase with decreasing temperature and with increasing concentration of sodium lactobionate. The Vogel–Tamman–Fulcher equation was used to correlate the dependence of density and viscosity on molality and temperature, and the refractive index was fitted by a polynomial model. The parameters were acquired by least-squares regression method for these models, and the calculated values showed good agreement with the experimental data for density, viscosity, and refractive index. The volumetric properties, including apparent molar volume, excess molar volume, and partial molar volume, among others, were determined according to the experimental values for sodium lactobionate mixtures. Furthermore, the relative viscosity and viscosity B coefficients were calculated. The molecule interactions and solution properties were studied on the basis of the evaluated thermodynamic property data. In the studied system, sodium lactobionate behaves as structure maker.

The solid–liquid phase equilibrium for the ternary succinic acid + adipic acid + ethanol system was determined at 283.15, 303.15, and 313.15 K, respectively, under about 101.3 kPa. The mutual solubility for the ternary system were obtained. At each temperature, there existed two pure solid phases in the ternary system, which were pure succinic acid and pure adipic acid, and identified by the Schreinemaker’s wet residue method and X-ray diffraction (XRD) pattern. The crystallization region of adipic acid was a little smaller than that of succinic acid at a certain temperature. The solid–liquid phase equilibrium for the ternary system was correlated and calculated by using the Wilson and NRTL models, and the corresponding binary interaction parameters were acquired. Results showed that calculated solubility values with NRTL model agreed better than those with the Wilson model. In addition, the densities of the equilibrium liquor were obtained and correlated with an empirical equation. The mutual solubility and the phase diagram for the ternary system are helpful in separating of succinic acid and adipic acid mixtures.

The solubility of 4-nitrophthalimide in different solvents are of great importance for the design of its purification process via crystallization. The work reported new solubility data for 4-nitrophthalimide in 12 pure solvents of methanol, ethanol, isopropanol, cyclohexanone, acetone, acetonitrile, ethyl acetate, 2-butanone, chloroform, 1,4-dioxane benzyl alcohol and N,N-dimethylformamide. They were determined by a high-performance liquid chromatography at T = (273.15 to 323.15) K under pressure of 0.1 MPa. The 4-nitrophthalimide solubility in the selected solvents increased with the temperature increase. At a given temperature, the solubility of 4-nitrophthalimide is largest in N,N-dimethylformamide and lowest in chloroform. The solubility data in the these solvents ranked as N,N-dimethylformamide > cyclohexanone > (1,4-dioxane, acetone, 2-butanone, benzyl alcohol) > ethyl acetate > acetonitrile > methanol > ethanol > isopropanol > chloroform. The experimental solubility data were correlated by modified Apelblat equation, λh equation, Wilson model, and NRTL model. The obtained values of root-mean-square deviation and relative average deviation are all less than 16.17 × 10–4 and 1.58%, respectively. The modified Apelblat equation achieved the best correlating results in totally.

In the present study, the solubility of 4,4′-dihydroxydiphenyl sulfone in mixed solvents of (acetone + methanol), (ethyl acetate + methanol), (acetonitrile + methanol), and (acetone + methanol) were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (278.15 to 313.15) K under atmosphere pressure. The solubility increased with increasing temperature in the binary solvent mixtures at constant solvent composition. At constant temperature and solvent composition, the dissolving capacity of 4,4′-dihydroxydiphenyl sulfone in the four binary solvent mixtures ranked as (acetone + ethanol) > (acetone + methanol) > (ethyl acetate + methanol) > (acetonitrile + methanol). The obtained solubility data were correlated by employing the Jouyban–Acree model, modified Apelblat–Jouyban–Acree model, Ma model and Sun model. The four models were proven to give good representation of the experimental solubility data. The largest value of relative average deviations (RAD) was 4.97 × 10–2, and that of root-mean-square deviations (RMSD) was 6.49 × 10–4. The experimental solubility and the models in this study could be helpful in separating 4,4′-dihydroxydiphenyl sulfone from its isomeric mixtures.

•Solubility of 2,4-dihydro-5-methyl-2-(4-methylphenyl)-3H-pyrazol-3-one in twelve solvents were determined.•The solubility were correlated with four thermodynamic models.•Mixing properties of the solutions were computed.The solubility of 2,4-dihydro-5-methyl-2-(4-methylphenyl)-3H-pyrazol-3-one in twelve organic solvents including methanol, ethanol, n-propanol, isopropanol, ethylbenzene, toluene, n-butanol, acetonitrile, ethyl acetate, 1,4-dioxane, cyclohexane and isopentanol were determined experimentally by using the isothermal saturation method over a temperature range from (278.15 to 313.15) K under 101.3 kPa. For the temperature range studied, the solubility of 2,4-dihydro-5-methyl-2-(4-methylphenyl)-3H-pyrazol-3-one in the solvents increased with a rise of temperature. The mole fraction solubility obeyed the following order from high to low in different solvents: isopentanol > 1,4-dioxane > n-butanol > n-propanol > ethyl acetate > methanol > ethanol > isopropanol > ethylbenzene > toluene > acetonitrile > cyclohexane. The obtained solubility data of 2,4-dihydro-5-methyl-2-(4-methylphenyl)-3H-pyrazol-3-one in the studied solvents were correlated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 1.35 × 10−4 and 0.32%, respectively. The RAD   values obtained with the modified Apelblat equation were smaller than those with the other three models for a given solvent. So the four thermodynamic models were all acceptable for the systems of 2,4-dihydro-5-methyl-2-(4-methylphenyl)-3H-pyrazol-3-one in these solvents. Furthermore, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient (γ1∞) and reduced excess enthalpy (H1E,∞) at infinitesimal concentration were calculated. The obtained solubility and thermodynamic studies would be very helpful for optimizing the purification process of 2,4-dihydro-5-methyl-2-(4-methylphenyl)-3H-pyrazol-3-one.

•Solubility of 4-nitrophthalimide in binary mixed solvents were determined.•Solubility data were correlated and calculated by four models.•The standard dissolution enthalpy for the dissolution processes were calculated.The solubility of 4-nitrophthalimide in binary (methanol + N,N-dimethylformamide (DMF), ethanol + DMF) and (acetone + DMF) solvent mixtures were investigated by the isothermal dissolution equilibrium method under atmosphere pressure. These studies were carried out at different mass fractions of methanol, ethanol or acetone ranging from 0.1 to 0.9 at temperature T = (273.15–323.15) K. For the nine groups of each solvent mixture studied, the solubility of 4-nitrophthalimide in mixed solutions increased with increasing temperature and mass fraction of methanol, ethanol or acetone for the three systems including (methanol + DMF), (ethanol + DMF) and (acetone + DMF). At the same temperature and mass fraction of methanol, ethanol or acetone, the mole fraction solubility of 4-nitrophthalimide in (acetone + DMF) was greater than that in the other two binary solvents. In addition, the experimental mole fraction solubility was correlated by four models (Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree model and Sun model). The Jouyban–Acree model gave best representation for the experimental solubility values. Furthermore, the standard molar enthalpies of 4-nitrophthalimide during the dissolving process (ΔsolHo) were also obtained in this work, and the results show that the dissolution process is endothermic. The experimental solubility and the models used in this work will be helpful in separating 4-nitrophthalimide from its isomeric mixtures.Graphical abstract

•Solubility of econazole nitrate in twelve pure organic solvents were determined.•Solubility data were correlated and calculated by modified Apelblat equation and λh equation.•The apparent dissolution enthalpy for the dissolution processes were calculated.The solubility of econazole nitrate (racemic mixture) in organic solvents is of clear importance for the design of separation processes and further theoretical studies. In this work, the solubilities of econazole nitrate in methanol, ethanol, n-butanol, isopropanol, ethyl acetate, 2-butanone, 3-methyl-1-butanol, acetonitrile, 1,4-dioxane, N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone (NMP) and acetone were determined at the temperatures from 278.15 K to 318.15 K under atmosphere pressure (p = 101.2 kPa) by high-performance liquid chromatography (HPLC). It was found that the econazole nitrate solubilities in mole fraction in selected solvents increased with the increase in temperature. At a given temperature, they obeyed the following order from high to low in different solvents: NMP > DMF > methanol > 2-butanone > acetone > (3-methyl-1-butanol, ethanol) > acetonitrile > n-butanol > isopropanol > 1,4-dioxane > ethyl acetate. The experimental solubility data were correlated with the modified Apelblat equation and the Buchowski–Książczak λh equation. The calculated solubilities using the modified Apelblat solubility model were in better agreement with the experimental values. The largest percentage of average relative deviation was 1.53% for solubility of econazole nitrate in isopropanol calculated with the λh equation, and the maximum value of root-mean-square deviation was 2.11 × 10−4. Based on the modified Apelblat equation, the apparent dissolution enthalpies of econazole nitrate in twelve pure solvent were derived. The results indicate that the dissolution of econazole nitrate in all studied cases is endothermic process.

•Solubility of 3-chloro-N-phenylphthalimide in ten solvents were determined.•The solubility were correlated with four models.•The solution properties were evaluated.The solubility of 3-chloro-N-phenylphthalimide in acetonitrile, methanol, n-propanol, isopropanol, n-butanol, 2-methyl-1-propanol, ethyl acetate, acetone, 1,4-dioxane and acetic acid were obtained experimentally with the high-performance liquid chromatography analysis at temperature ranging from (288.15 to 323.15) K under 0.1 MPa. The solubility values of 3-chloro-N-phenylphthalimide in those solvents increased with an increase in temperature, and decreased from high to low based on the following order: 1,4-dioxane > acetone > ethyl acetate > acetonitrile > acetic acid > (n-propanol, n-butanol) > (methanol, 2-methyl-1-propanol) > isopropanol. The obtained solubility data of 3-chloro-N-phenylphthalimide in the studied solvents were correlated by using four models, the modified Apelblat equation, λh equation, Wilson model and NRTL model. The calculated solubility using the modified Apelblat equation provided better agreement with those evaluated by the other three models. In general, the four models were all acceptable for correlating the solubility data of 3-chloro-N-phenylphthalimide in the studied solvents. In addition, the change of molar Gibbs energy, molar solution enthalpy, molar solution entropy and excess enthalpy of the solution for per 1 mol of mixture of 3-chloro-N-phenylphthalimide in these solvents were evaluated at mean harmonic temperature. The dissolution process of 3-chloro-N-phenylphthalimide in the selected solvents was exothermic and entropy-driving. The study concerning the solubility of 3-chloro-N-phenylphthalimide in the selected solvents and solution properties can provide fundamental data in the manufacturing and separating process of 3-chloro-N-phenylphthalimide.

•Solubility of ACET in four groups mixed solvents were determined.•Solubility data were correlated and calculated by three cosolvency models.•The standard dissolution enthalpy for the dissolution processes were calculated.The solubility of ethyl 5-amino-4-cyano-3-(2-ethoxy-2-oxoethyl)-2-thiophenecarboxylate (ACET) in binary (acetone + methanol), (acetone + ethanol), (acetone + 1-butanol) and (acetone + isopropanol) solvent mixtures was investigated by the isothermal dissolution equilibrium method under 101.3 kPa. This study was carried out at different mass fractions of acetone ranging from 0.1 to 0.9 at T = (273.15–318.15) K. For the nine groups with each solvent mixture studied, the solubility of ACET in the mixed solutions increased with increasing temperature and mass fraction acetone. At the same temperature and mass fraction of acetone, the solubility of ACET was greater in (acetone + methanol) than in the other three solvent mixtures. The experimental solubility values were correlated by three co-solvency models (Jouyban-Acree model, van’t Hoff-Jouyban-Acree model and Apelblat- Jouyban-Acree model). The relative average deviations (RAD) and the root-mean-square deviations (RMSD) were all less than 1.49 × 10−2 and 8.99 × 10−4, respectively. The Apelblat-Jouyban-Acree model provided best representation of the experimental solubility. Furthermore, the standard molar enthalpy of the ACET during the dissolving process (ΔsolHoΔsolHo) was also derived in this work, and the results showed that the dissolution process is endothermic. The experimental solubility and the models used in this work would be helpful in purifying of ACET from its crude mixtures.

•Solubility of 2,4′-dihydroxydiphenyl sulfone in nine pure solvents were determined.•The solubility were correlated by using four thermodynamic models.•The standard molar dissolution enthalpy and excess enthalpy of solution were calculated.The solubility of 2,4′-dihydroxydiphenyl sulfone in methanol, ethanol, acetone, acetonitrile, ethyl acetate, 1,4-dioxane, n-butanol, isopropanol and 2-butanone was determined at temperatures from (278.15 to 313.15) K under 101.2 kPa by using the high-performance liquid chromatography (HPLC). With the increase in temperature, the solubility of 2,4′-dihydroxydiphenyl sulfone in these solvents increased. Generally, the mass fraction solubility followed the sequence from high to low in different solvents except for 1,4-dioxane: acetone > methanol > (2-butanone, ethanol) > isopropanol > n-butanol > ethyl acetate > acetonitrile. The solubility of 2,4′-dihydroxydiphenyl sulfone in 1,4-dioxane showed the strongest positive dependency on temperature. The measured solubility of 2,4′-dihydroxydiphenyl sulfone were correlated by using four thermodynamic models, which corresponded to the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of RMSD and RAD were 9.52 × 10−4 and 1.54%, respectively. By comparing the four models, the computed solubility using the modified Apelblat equation provided better agreement with the experimental values than those using the other three models. On the whole, the four models were all acceptable for describing the solubility of 2,4′-dihydroxydiphenyl sulfone in the selected solvents. In addition, the standard molar dissolution enthalpy and excess enthalpy of solution of 2,4′-dihydroxydiphenyl sulfone in the solvents were evaluated. The dissolution process of 2,4′-dihydroxydiphenyl sulfone in the selected solvents was endothermic. The study on the solubility of 2,4′-dihydroxydiphenyl sulfone in the selected solvents and solution properties can provide fundamental data in the separating process of 2,4′-dihydroxydiphenyl sulfone from its isomeric mixtures.

•SLE formed by 1,5 and/or 1,8-dinitronaphthalene and NMP was determined.•The binary and ternary phase diagrams were constructed.•The phase diagrams were correlated and calculated using thermodynamic models.The solubility of 1,8-dinitronaphthalene and 1,5-dinitronaphthalene in N-methyl-2-pyrrolidone at (293.15–343.15) K and the mutual solubility of the ternary 1,5-dinitronaphthalene + 1,8-dinitronaphthalene + N-methyl-2-pyrrolidone mixture at (313.15, 328.15 and 343.15) K were determined experimentally using the isothermal saturation method under atmospheric pressure (101.2 kPa). The solubility of 1,8-dinitronaphthalene in N-methyl-2-pyrrolidone is larger than that of 1,5-dinitronaphthalene. Three isothermal ternary phase diagrams were built according to the measured mutual solubility data. In each ternary phase diagram, there were one co-saturated point, two boundary curves, and three crystalline regions. Two pure solids (pure 1,8-dinitronaphthalene and pure 1,5-dinitronaphthalene) were formed in the ternary system at a given temperature, which were identified by Schreinemaker’s method of wet residue and powder X-ray diffraction (PXRD) pattern. The crystallization region of 1,8-dinitronaphthalene was smaller than that of 1,5-dinitronaphthalene at each temperature. The modified Apelblat equation, λh equation, NRTL model and Wilson model were used to correlate the solubility of 1,8-dinitronaphthalene and 1,5-dinitronaphthalene in N-methyl-2-pyrrolidone; and the NRTL and Wilson models were employed to correlate and calculate the mutual solubility for the ternary 1,5-dinitronaphthalene + 1,8-dinitronaphthalene + N-methyl-2-pyrrolidone system. The largest value of root-mean-square deviation (RMSD) was 20.34 × 10−4 for the binary systems; and 7.38 × 10−3 for ternary system. The calculated results via these models are all acceptable for the binary and ternary solid-liquid phase equilibrium.

•Solubilities of dehydroepiandrosterone acetate in mixed solvents were determined.•The measured solubility data were correlated with three thermodynamic models.•The standard dissolution enthalpies of dehydroepiandrosterone acetate were calculated.The solubility of dehydroepiandrosterone acetate in binary solvent mixtures of (ethyl acetate + methanol), (ethyl acetate + ethanol) and (ethyl acetate + isopropanol) was determined experimentally by using an isothermal dissolution equilibrium method within the temperature range from (273.15 to 313.15) K under atmosphere pressure (101.1 kPa). The solubility of dehydroepiandrosterone acetate increases with increasing temperature and mass fraction of ethyl acetate in each binary system. At the same temperature and mass fraction of ethyl acetate, the solubility of dehydroepiandrosterone acetate was greater in (ethyl acetate + isopropanol) than in the other two mixed solvents. The measured solubility values were correlated with the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model, and modified Apelblat-Jouyban-Acree model. The Jouyban-Acree model was proven to give better representation for the experimental solubility, which provided the lowest relative average deviation and root-mean-square deviation (0.49 × 10−2 and 0.97 × 10−4 for ethyl acetate + methanol, 0.44 × 10−2 and 0.82 × 10−4 for ethyl acetate + ethanol, and 0.92 × 10−2 and 3.05 × 10−4 for ethyl acetate + isopropanol, respectively). Based on the solubility values obtained, the standard dissolution enthalpies for the dissolution process were computed. The dissolution process of dehydroepiandrosterone acetate in these mixed solvents was endothermic. The experimental solubility and the equations presented in the present work can be employed as essential data and models in the practical process for production and purification of dehydroepiandrosterone acetate.

•Solubility of 1,8-dinitronaphthalene in mixed solvents were determined.•The measured solubility data were correlated with five thermodynamic models.•The dissolution enthalpy of 1,8-dinitronaphthalene in mixed solvents were calculated.The solubility of 1,8-dinitronaphthalene in mixed solvents of (acetone + methanol), (toluene + methanol) and (acetonitrile + methanol) were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (273.15 to 313.15) K under 101.3 kPa. The solubility of 1,8-dinitronaphthalene increased with increasing temperature and mass fraction of acetone or acetonitrile for the systems (acetone + methanol) and (acetonitrile + methanol). For the (toluene + methanol) system, at a certain composition of toluene, the solubility of 1,8-dinitronaphthalene increased with an increase in temperature; nevertheless at the same temperature, they increased at first and then decreased with an increase in mass fraction of toluene. At the same temperature and mass fraction of acetone, acetonitrile or toluene, the solubility of 1,8-dinitronaphthalene in acetone was greater than that in two others. The obtained solubility data were correlated by employing Jouyban–Acree model, van’t Hoff–Acree model, modified Apelblat–Acree model, Ma model and Sun model. The Jouyban–Acree model was proven to give good representation of the experimental solubility data. On the base of the measured solubility, the dissolution enthalpies of the dissolution process were calculated. Dissolution of 1,8-dinitronaphthalene in these mixed solvents is an endothermic process.

•Solubility of 3,5-dichloroaniline in seven organic solvents were determined.•Solid–liquid phase equilibrium for ternary system was measured.•The binary and ternary phase diagrams were constructed.•The phase diagrams were correlated with thermodynamic models.The solid–liquid phase equilibrium data for 3,5-dichloroaniline in n-propanol, isopropanol, n-butanol, isobutanol, toluene, ethyl acetate and acetone at (283.15 to 308.15) K were determined experimentally by gas chromatography under 101.3 kPa. The solubility of 3,5-dichloroaniline in these solvents decreased according to the following order: ethyl acetate > (acetone, toluene) for the solvents of ethyl acetate, acetone, and toluene; and for the other solvents, (isopropanol, n-butanol) > n-propanol > isobutanol. According to the solubility of 3,5-dichloroaniline in pure solvents, the solid–liquid phase equilibrium for the ternary mixture of 3,5-dichloroaniline + 1,3,5-trichlorobenzene + toluene were measured by using an isothermal saturation method at three temperatures of 283.15, 293.15, and 303.15 K under 101.3 kPa, and the corresponding isothermal phase diagrams were constructed. Two pure solids were formed in the ternary system at a fixed temperature, which were pure 3,5-dichloroaniline and pure 1,3,5-trichlorobenzene and were identified by Schreinemakers’ method of wet residue. The temperature dependence of 3,5-dichloroaniline solubility in pure solvents was correlated by the modified Apelblat equation, λh equation, Wilson model and NRTL model; and the ternary solid–liquid phase equilibrium of 3,5-dichloroaniline + 1,3,5-trichlorobenzene + toluene were described by the Wilson model and NRTL model. Results showed that calculated solubility values with these models agreed well with the experimental ones for the studied binary and ternary systems. The solid–liquid equilibrium and the thermodynamic models for the binary and ternary systems can offer the foundation for purification of 3,5-dichloroaniline from its mixture.

•Solubility data for the system of terephthalic acid + isophthalic acid + phthalic acid + N-methyl-2-pyrrolidone were determined.•The quaternary phase diagrams were constructed at two temperatures according to the Jãneck method.•The quaternary solid–liquid phase equilibrium was predicted by NRTL model.Solid–liquid phase equilibrium and solubility data for quaternary system of terephthalic acid + isophthalic acid + phthalic acid + N-methyl-2-pyrrolidone at 303.15 K and 313.15 K were determined by Schreinemakers’ method of wet residue under atmosphere pressure. Based on the measured solubility, the quaternary phase diagrams were constructed at the two studied temperatures according to the Jãneck method. At each temperature, the quaternary phase diagram includes three crystallization regions of pure solid, three co-saturated curves and one eutectic point. The three pure solids are phthalic acid, adduct of isophthalic acid with N-methyl-2-pyrrolidone (the mole ratio of isophthalic acid to N-methyl-2-pyrrolidone is 1:2), adduct of terephthalic acid with N-methyl-2-pyrrolidone (the mole ratio of terephthalic acid to N-methyl-2-pyrrolidone is 1:2), which are confirmed by the method of Schreinemakers’ wet residue. The crystallization region of adduct of terephthalic acid with N-methyl-2-pyrrolidone is larger than those of phthalic acid and adduct of isophthalic acid with N-methyl-2-pyrrolidone. Furthermore, the quaternary solid–liquid phase equilibrium were predicted by NRTL model. The calculated quaternary phase diagrams agreed well with experimental data.

•The saturated vapor pressures for 4-fluorophthalic anhydride and 4-chlorophthalic anhydride were measured.•The isobaric VLE data were obtained for the 4-fluorophthalic anhydride + 4-chlorophthalic anhydride system.•The experimental VLE data were correlated by Wilson model, NRTL model and UNIQUAC model.The saturated vapor pressures of 4-fluorophthalic anhydride and 4-chlorophthalic anhydride at various temperatures ranging from T = (426 to 560) K, and the isobaric vapor–liquid phase equilibrium data for binary system of 4-fluorophthalic anhydride (1) + 4-chlorophthalic anhydride (2) at pressures of 21.33 kPa, 41.33 kPa, 61.33 kPa and 81.33 kPa were measured experimentally by means of an inclined ebulliometer. The relationship between saturated vapor pressure and temperature was fitted by using two Antoine equations and the Antoine constants were acquired for 4-fluorophthalic anhydride and 4-chlorophthalic anhydride, respectively. The semi-empirical method, Herington method was employed to test thermodynamic consistency of the vapor–liquid equilibrium data. The isobaric vapor–liquid phase equilibrium data were fitted with three thermodynamic models, which corresponded to Wilson, NRTL and UNIQUAC. The parameters of the three activity coefficient models were obtained by the method of nonlinear least-square regression. The calculated vapor–liquid phase equilibrium data with the three activity coefficient models agree very well with the experimental values.

The solubility of 3,3′,4,4′-oxydiphthalic anhydride in binary solvents of (acetic acid + water) and (propionic acid + water) at temperatures ranging from 278.15 to 313.15 K were measured using a gravimetric method. The measured solubility data of 3,3′,4,4′-oxydiphthalic anhydride in (acetic acid + water) and (propionic acid + water) mixed solvents exhibit monotonic behavior under the studied conditions. The solubilities increased with increasing of both temperature and mass fraction of acetic acid or propionic acid. The solubility values were correlated by the three parameters equation, the \( \lambda h \) equation, the NRTL model and the binary solvent models, the Ma model and the Sun model. The calculated values by the five models agreed well with the experimental data for the solubility of 3,3′,4,4′-oxydiphthalic anhydride in (acetic acid + water) and (propionic acid + water) solutions. The standard thermodynamic properties of dissolution of 3,3′,4,4′-oxydiphthalic anhydride, including the dissolution Gibbs energy change (\( \Delta _{\text{sol}} G_{{}}^{\text{o}} \)),molar dissolution enthalpy change (\( \Delta _{\text{sol}} H_{{}}^{\text{o}} \)) and molar dissolution entropy change (\( \Delta _{\text{sol}} S_{{}}^{\text{o}} \)) were calculated from the experimentally measured solubility data. The values of the change of standard molar enthalpy are positive, which shows that the dissolution process of 3,3′,4,4′-oxydiphthalic anhydride in the binary system of (acetic acid + water) and (propionic acid + water) is endothermic.

•The saturated vapor pressure of pure 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene was measured.•The isobaric vapor–liquid equilibrium data were measured for 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene system.•The vapor–liquid equilibrium data were correlated with Wilson, NRTL and UNIQUAC models.The saturated vapor pressures of pure 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene and the isobaric vapor–liquid equilibrium (VLE) data for binary 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene system under 20.00 kPa, 60.00 kPa and 101.30 kPa were measured experimentally using an inclined ebulliometer. The saturated vapor pressure was correlated by an Antoine equation. Thermodynamic consistency of the vapor–liquid equilibrium data was tested by means of Herington semi-empirical method, and the vapor–liquid equilibrium data were correlated with Wilson, NRTL and UNIQUAC activity coefficient models. The parameters of the three thermodynamic models were obtained by a nonlinear least-square regression method. All the three models can describe the measured vapor–liquid data satisfactorily. The vapor pressures and the vapor–liquid equilibrium data presented in the paper are essential for the design and operation for separation of the isomeric mixture of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene via distillation.

The solubilities of 2,3-dichloronitrobenzene in aqueous solutions of methanol and ethanol with various concentrations were determined at temperatures ranging from (278.15 to 303.15) K under atmospheric pressure of 0.1 MPa. The solubility of 2,3-dichloronitrobenzene increases with increments in both temperature and mass fraction of methanol or ethanol. The solubility data were correlated by five models, which are the Jouyban–Acree model, van't Hoff–Acree model, modified Apelblat–Acree model, Ma model, and Sun model. The calculated solubility using the Jouyban–Acree model shows better agreement with the experimental data than those by the other models. The thermodynamic properties, molar dissolution enthalpy, molar dissolution entropy, and Gibbs free energy change of dissolution process of 2,3-dichloronitrobenzene in two mixed solvents were calculated.

The solid–liquid phase equilibrium and solubility of 3,5-dichloroaniline were determined in mixed solvents of (methanol + water) and (ethanol + water) in temperatures ranging from (278.15 to 303.15) K under normal pressure (0.1 MPa). The solubility of 3,5-dichloroaniline in the mixed solvents increased with increasing temperature and mass fraction of methanol or ethanol. At the same temperature and mass fraction of methanol or ethanol, the solubility of 3,5-dichloroaniline in ethanol was greater than that in methanol. The Modified Apelblat equation and λh equation were employed to fit the solubility data. Results indicated that the Modified Apelblat equation was proven to give good representations of the experimental solubility data. According to the measured solubility, the thermodynamic properties such as dissolution enthalpy, dissolution entropy, and change of molar Gibbs free energy of the dissolution process were calculated. Dissolution of 3,5-dichloroaniline in aqueous alcohols is an endothermic process.

The solubility of 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene in ethyl acetate, tetrachloromethane, cyclohexane, hexane, heptane, 1-propanol, 2-propanol, and 1-butanol were measured experimentally under temperatures of (278.15 to 303.15) K by employing the gravimetric method. The solubility of 3,4-dichloronitrobenzene or 2,3-dichloronitrobenzene in all organic solvents studied increases with increasing in temperature. Four models, the modified Apelblat equation, λh equation, Wilson model, and nonrandom two-liquid (NRTL) model, were employed to correlate the measured solubility. Results indicated that the modified Apelblat equation was the better model than the other models. The solubility data would be very useful for optimizing the purification process of 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene on the industrial scale.

In this paper, the mutual solubility for ternary system of 4-chlorophthalic anhydride + 3-chlorophthalic anhydride + ethyl acetate was measured experimentally at different temperatures. Four isothermal phase diagrams of the system were constructed based on the measured solubility. At each temperature, there existed two pure solid phases, pure 4-chlorophthalic anhydride and pure 3-chlorophthalic anhydride, which were identified by the Schreinemakers’ wet residue method. When temperature decreases, the crystallization regions of 4-chlorophthalic anhydride and 3-chlorophthalic anhydride increase. At a certain temperature, the crystallization region of 4-chlorophthalic anhydride is smaller than that of 3-chlorophthalic anhydride.

In this work, solid–liquid equilibria (SLE) data for the ternary 3-nitrophthalic anhydride + 4-nitrophthalic anhydride + 1,4-dioxane system were obtained at (283.15, 303.15, and 323.15) K. The solid–liquid phase diagrams of the ternary system were constructed based on the measured solubility data. There existed two pure solid phases at each temperature in the studied system, pure 3-nitrophthalic anhydride and 4-nitrophthalic anhydride, which were identified by the wet residue method of Schreinemaker. Furthermore, the density (ρ) of the equilibrium liquid phase was determined. The ternary phase diagram and solubility data for the system 3-nitrophthalic anhydride + 4-nitrophthalic anhydride + 1,4-dioxane, which shows a much more practical application for the region where pure 3-nitrophthalic anhydride and 4-nitrophthalic anhydride are obtained, are much larger than those in the system with 2-propanone as a solvent.

•We measured the solid–liquid phase equilibrium for ternary system of 4-chlorophthalic anhydride + 3-chlorophthalic anhydride + acetone.•We constructed four isothermal phase diagrams.•We calculated the experimental solid–liquid phase equilibrium for ternary system using the Wilson and NRTL models.The solid–liquid phase equilibrium for ternary system of 4-chlorophthalic anhydride + 3-chlorophthalic anhydride + acetone was measured at different temperatures and the mutual solubility was obtained. Four isothermal phase diagrams were constructed according to the experimental solubility. There existed two pure solid phases at each temperature in the studied system, pure 4-chlorophthalic anhydride and pure 3-chlorophthalic anhydride, which were identified by the wet residue method of Schreinemakers’. The crystallization regions of the pure two solids increase with the decrease in temperature. The experimental solid–liquid phase equilibrium for ternary system was calculated using the Wilson and NRTL models, and the corresponding binary interaction parameters were obtained according to the solubility of binary system. The calculated results agree well with the experimental data at different temperature. Both the models give acceptable results for the investigated systems.

The solubility of sodium 2,4-diaminobenzenesulfonate in binary NaCl + H2O, Na2SO4 + H2O, and C2H5OH + H2O solvent mixtures were measured at elevated temperatures from 273.15 K to 323.15 K by a steady-state method. The results of these data were correlated by a modified Apelblat equation.

The solubilities of 3,4-dichloronitrobenzene in methanol, ethanol, and liquid mixtures (methanol + water, ethanol + water) were measured in the temperature range of (278.15 to 303.15) K at 101.3 kPa by gas chromatography. The solubility of 3,4-dichloronitrobenzene in the binary mixed solvents increased with both increasing temperature and mass fraction of organic solvents. The measured solubility was correlated by the van’t Hoff equation, the modified Apelblat equation, and the λh equation. The correlated results indicated that the calculated solubility using the modified Apelblat equation had a closer agreement with the experimental data than those using the other two models. According to the measured solubility, the thermodynamic properties of dissolution of 3,4-dichloronitrobenzene, including the Gibbs free energy change of solution, molar enthalpy of dissolution, and molar entropy of dissolution, were calculated by using the modified Apelblat model.

The saturated vapor pressure of pure 3,5-dichloroaniline was measured from (10.25 to 95.81) kPa in the temperature range from (446.60 to 534.94) K using an ebulliometer. The results were fitted by an Antoine equation using a nonlinear least-squares regression method. The calculated saturated vapor pressure agrees well with the experimental values. The ideal gas molar enthalpy and ideal gas entropy of vaporization (ΔgidlHm, ΔgidlSm) of 3,5-dichloroaniline in the temperature range from (446.60 to 534.94) K were calculated by the combination of the Clausius–Clapeyron equation and Antoine equation.

The solid−liquid phase equilibrium and mutual solubility for the ternary 3-chlorophthalic acid + 4-chlorophthalic acid + water system were determined at (283.15 and 313.15) K. The phase diagrams of the system were constructed on the basis of the measured solubility. The solid phases formed in the studied system were confirmed by Schreinemaker’s method of wet residues. At (283.15 and 313.15) K, both 3-chlorophthalic acid and 4-chlorophthalic acid were formed in the ternary 3-chlorophthalic acid + 4-chlorophthalic acid + water system. Besides, an adductive compound with the formula (3-C6H3Cl(COOH)2·4-C6H3Cl(COOH)2) existed. The crystallization field of 3-chlorophthalic acid was larger than that of the adduct or 4-chlorophthalic acid at each studied temperature. The solubility data and the ternary phase diagram for the system of 3-chlorophthalic acid + 4-chlorophthalic acid + water at (283.15 and 313.15) K can provide the fundamental basis for the preparation of 3-chlorophthalic anhydride from 3-chlorophthalic anhydride and 4-chlorophthalic anhydride mixtures.

The solubilities of sodium 2,6-naphthalene disulfonate and sodium 2,7-naphthalene disulfonate in aqueous solutions of sulfuric acid were measured in the temperature range from (283.15 to 333.15) K by a steady-state method. The solubility of sodium 2,6-naphthalene disulfonate or sodium 2,7-naphthalene disulfonate increases with the increase in temperature from (283.15 to 333.15) K. With the increase in sulfuric acid concentrations, the solubilities of sodium 2,6-naphthalene disulfonate and sodium 2,7-naphthalene disulfonate decrease. At the same temperature and in the same composition of sulfuric acid + water solvent mixtures, the solubility of sodium 2,7-naphthalene disulfonate is larger than that of sodium 2,6-naphthalene disulfonate. Results of these measurements were correlated by a modified Apelblat equation.

(Solid + liquid) phase equilibrium (SLE) has been measured for 4-chloro-2-benzofuran-1,3-dione anhydride and 5-chloro-2-benzofuran-1,3-dione anhydride using differential scanning calorimetry (DSC) over the whole concentration range. It was found that this system is a simple eutectic system. The eutectic point is at T = 336.95 K and a mole fraction of 4-chloro-2-benzofuran-1,3-dione of 0.3482. Furthermore, the results obtained in mixtures of (4-chloro-2-benzofuran-1,3-dione and 5-chloro-2-benzofuran-1,3-dione) have been compared with those predicted by the ideal model and correlated by Wilson and nonrandom two-liquid (NRTL) equations. The best modeling results were obtained using the NRTL model with the average root-mean-square deviation of σ = 7.88 K.

The mutual solubility for the ternary p-nitroaniline + o-nitroaniline + ethanol system was measured at (273.15 to 323.15) K. Three isothermal phase diagrams of the system were constructed on the basis of the measured solubilities. The phase diagrams of the ternary system were similar at all temperatures investigated. Two solid phases were formed and confirmed by the Schreinemaker’s wet residue method; one was p-nitroaniline, and the other was o-nitroaniline. The crystallization regions of p-nitroaniline and o-nitroaniline increase as the temperature decreases. At the same temperature, the crystallization region of p-nitroaniline is larger than that of o-nitroaniline.

•Solubility of succinic acid in diethylene glycol was determined.•Solubility of succinic acid + urea + diethylene glycol was determined.•Three ternary phase diagrams were constructed for the ternary system.•The ternary phase diagrams were correlated using NRTL model.In this work, the solid-liquid phase equilibrium for binary system of succinic acid + diethylene glycol at the temperatures ranging from (298.15 to 333.15) K and ternary system of (succinic acid + urea + diethylene glycol) at 298.15 K, 313.15 K and 333.15 K was built by using the isothermal saturation method under atmospheric pressure (101.2 kPa), and the solubilities were determined by a high-performance liquid chromatography. The solid-phases formed in the ternary system of ((succinic acid + urea + diethylene glycol)) were confirmed by Schreinemaker’s method of wet residue, which corresponded to urea, succinic acid, and adduct 2:1 urea-succinic acid (mole ratio). Three isothermal phase diagrams for the ternary system were constructed based on the measured mutual solubility. Each isothermal phase diagram included six crystallization fields, three invariant curves, two invariant points and two co-saturated points. The crystalline region of adduct 2:1 urea-succinic acid is larger than those of the other two solids. The solubility of succinic acid in diethylene glycol was correlated with the modified Apelblat equation, λh equation and NRTL model; and the mutual solubility of the ternary ((succinic acid + urea + diethylene glycol)) system was correlated and calculated by the NRTL model. The interaction parameters’ values of succinic acid-urea were acquired. The value of RMSD was 7.11 × 10−3 for the ternary system. The calculation results had good agreement with the experiment values. Furthermore, the densities of equilibrium liquid phase were acquired. The phase diagrams and the thermodynamic model of the ternary system could provide the basis for design of the adductive crystallization process which was used to separate succinic acid with high purity from dicarboxylic acid mixtures.

•Solubility of 2-amino-4-chlorobenzoic acid in eleven solvents were determined.•Four thermodynamic models were employed to correlate the solubility data.•The mixing properties of solutions were calculated.The solubility of 2-amino-4-chlorobenzoic acid in eleven organic solvents including N-methyl-2-pyrrolidone, ethanol, n-propanol, isopropanol, ethyl benzene, toluene, n-butanol, acetonitrile, ethyl acetate, 1,4-dioxane and acetone were determined experimentally using the isothermal saturation method over a temperature range from (278.15 to 313.15) K under 101.2 kPa. Within the temperature range studied, the mole fraction solubility of 2-amino-4-chlorobenzoic acid in the solvents increased with a rise of temperature. On the whole, they obeyed the following order from high to low in the selected solvents: N-methyl-2-pyrrolidone > acetone > 1, 4-dioxane > ethyl acetate > ethanol > isopropanol > n-propanol > n-butanol > acetonitrile > toluene > ethyl benzene. The solubility values obtained for 2-amino-4-chlorobenzoic acid were correlated with the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 8.25 × 10−4 and 3.35%, respectively. The modified Apelblat equation correlated the experimental solubility best on the basis of the result of AIC   analysis. Furthermore, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient (γ1∞) and reduced excess enthalpy (H1E,∞) at infinitesimal concentration were determined. Solubility and thermodynamic studies are very important for optimizing the purification process of 2-amino-4-chlorobenzoic acid.

•Solubilities of tebuconazole in nine organic solvents were determined.•The solubilities were correlated by using four thermodynamic models.•The mixing properties of solution were computed based on Wilson model.The solubility of tebuconazole in nine organic solvents including methanol, ethanol, isopropanol, n-propanol, ethyl acetate, toluene, acetone, 2-butanone and acetonitrile was determined experimentally by using the isothermal saturation method over a temperature range from (278.15 to 313.15) K under 101.2 kPa. For the temperature range investigated, the mole fraction solubility of tebuconazole in the solvents increased with a rise of temperature. On the whole, they obeyed the following order from high to low in different solvents: 2-butanone > acetone > (ethyl acetate, toluene) > methanol > ethanol > isopropanol > n-propanol > acetonitrile. The acquired solubility data of tebuconazole in the studied solvents were correlated by using the modified Apelblat equation, λh equation, Wilson and NRTL models. The maximum values of root-mean-square deviation (RMSD) was 12.35 × 10−4, and the relative average deviation (RAD), 1.56%. Generally, the four thermodynamic models could all be employed to describe the solubility behaviour of tebuconazole in these solvents, and the modified Apelblat equation correlated the experimental data best according to the result of Akaike Information Criterion (AIC  ) analysis. Furthermore, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were computed. The solubility obtained and thermodynamic studies should be very helpful for optimizing the purification process of tebuconazole.

•Solubility of phthalimide solubility in three binary mixed solvents were determined.•Solubility data were correlated and calculated by four models.•The standard dissolution enthalpy for the dissolution processes were computed.The solubilities of phthalimide in mixed solvents of (acetone + methanol), (ethyl acetate + methanol) and (acetonitrile + methanol) were determined experimentally by using the isothermal dissolution equilibrium method within the temperature range from (283.15 to 318.15) K under atmospheric pressure (101.1 kPa). For the three systems of (acetone + methanol), (ethyl acetate + methanol) and (acetonitrile + methanol), at a fixed composition of acetonitrile, acetone or ethyl acetate, the solubility of phthalimide increased with an increase in temperature; however, at the same temperature, they increased at first and then decreased with the increase in mass fraction of acetonitrile, acetone or ethyl acetate. At the same temperature and mass fraction of acetonitrile, acetone or ethyl acetate, the mole fraction solubility of phthalimide in (acetone + methanol) was greater than those in the other mixed solvents. The solubility values obtained were correlated with Jouyban-Acree model, van’t Hoff-Jouyban-Acree model, modified Apelblat-Jouyban-Acree model and CNIBS/R-K model. The maximum values of relative average deviations (RAD) and root-mean-square deviations (RMSD) between the experimental and calculated solubility were 5.64 × 10−2 and 11.56 × 10−4, respectively. The CNIBS/R-K model proved to provide the best representation of the experimental results. In addition, the standard dissolution enthalpies of the dissolution process were calculated on the basis of the measured solubility. Dissolution of phthalimide in these mixed solvents is an endothermic process.

•Solubility of 2-amino-5-methylthiazole in eleven pure solvents was determined.•The solubility data were correlated with four solubility models.•The mixing properties were calculated.Solubility of 2-amino-5-methylthiazole in methanol, ethanol, n-propanol, isopropanol, acetone, 2-butanone, acetonitrile, ethyl acetate, toluene, 1,4-dioxane and cyclohexane were determined by using the isothermal saturation method over a temperature range from (278.15 to 313.15) K under atmosphere pressure (101.2 kPa). The solubility of 2-amino-5-methylthiazole in the studied solvents increased with the increase in temperature, and the mole solubility obeyed the following order from high to low in different solvents: methanol > ethyl acetate > acetone > ethanol > 1,4-dioxane > (2-butanone, n-propanol) > isopropanol > acetonitrile > toluene > cyclohexane. The attained solubility data of 2-amino-5-methylthiazole were correlated by using the modified Apelblat equation, λh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 10.66 × 10− 4 and 1.74%, respectively. Furthermore, the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration and reduced excess enthalpy were evaluated.

•SLE for ternary system of succinic acid + glutaric acid + ethanol was determined.•The ternary phase diagrams were constructed at 283.15 K, 303.15 K and 313.15 K.•The phase diagrams were correlated and calculated by NRTL and Wilson models.•The densities of the equilibrium liquid phase were obtained and correlated.The solid-liquid phase equilibrium for ternary system of succinic acid + glutaric acid + ethanol was determined by an isothermal saturation method at the three temperatures of (283.15, 303.15 and 313.15) K under atmosphere pressure. Three isothermal phase diagrams were built based on the measured mutual solubility data. There were two pure solids formed in the ternary system at a certain temperature, which corresponded to pure succinic acid and pure glutaric acid and were confirmed by Schreinemaker’s method of wet residue and X-ray powder diffraction. The ternary phase diagram included one co-saturated point, two boundary curves, and three crystalline regions. The crystallization region of glutaric acid was smaller than that of succinic acid at each temperature. In addition, two thermodynamic models, NRTL and Wilson were employed to correlate and calculate the mutual solubility data for the ternary succinic acid + glutaric acid + ethanol system. The largest RMSD value for the ternary system of succinic acid + glutaric acid + ethanol was 0.43, and the maximum value of RAD was 3.0%. The Wilson model and NRTL model may all be employed to describe the mutual solubility behavior for the ternary system of succinic acid + glutaric acid + ethanol at various temperatures. Furthermore, the densities of the equilibrium liquid phase were obtained and correlated with an empirical equation.