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In this work, a series of CuCo2O4-x (x = N, A and C) catalysts were synthesized using different metal salt precursors by urea hydrothermal method for catalytic soot combustion. The effect of CuCo2O4-x catalysts on soot conversion and CO2 selectivity in both loose and tight contact mode was investigated. The CuCo2O4-N catalyst exhibited outstanding catalytic activity with the characteristic temperatures (T10, T50 and T90) of 451 °C, 520 °C and 558 °C, respectively, while the CO2 selectivity reached 98.8% during the reaction. With the addition of NO, the soot combustion was further accelerated over all catalysts. Compared with the loose contact mode, the soot conversion was improved in the tight contact mode. The CuCo2O4-N catalysts showed better textural properties compared to the CuCo2O4-A and CuCo2O4-C, such as higher specific surface areas and pore volumes. The XRD results confirmed that the formation of a CuCo2O4 crystal phase in all catalysts. However, the CuO crystal phase only presented in CuCo2O4-N and CuCo2O4-A. The relative contents of Cu2+, Co3+ and Oads on the surface of CuCo2O4-x (x = N, A and C) catalysts were analyzed by XPS. The CuCo2O4-N catalyst displayed the highest relative content of Cu2+, Co3+ and Oads. The activity of catalytic soot combustion showed a good correlation with the order of the relative contents of Cu2+, Co3+ and Oads. Additionally, the CuCo2O4-N catalyst exhibited lower reduction temperature compared to the CuCo2O4-A and CuCo2O4-C. The cycle tests clarified that the copper–cobalt spinel catalyst obtained good stability. In addition, based on the Mars–van Krevelen mechanism, the process of catalytic soot combustion was described combined with the electron transfer process and the role of oxygen species over CuCo2O4 spinel catalysts.

To establish a survival prognostic model for pseudomyxoma peritonei (PMP) treated with cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) based on Bayesian network (BN).453 PMP patients were included from the database at our center. The dataset was divided into a training set to establish BN model and a testing set to perform internal validation at a ratio of 8:2. From the training set, univariate and multivariate analyses were performed to identify independent prognostic factors for BN model construction. The confusion matrix, receiver operating characteristic (ROC) curve and the area under curve (AUC) were used to evaluate the performance of the BN model.The univariate and multivariate analyses identified 7 independent prognostic factors: gender, previous operation history, histological grading, lymphatic metastasis, peritoneal cancer index, completeness of cytoreduction and splenectomy (all p 0.05). Based on independent factors, the BN model of training set was established. After internal validation, the accuracy and AUC of the BN model were 70.3% and 73.5%, respectively.The BN model provides a reasonable level of predictive performance for PMP patients undergoing CRS + HIPEC.

In response to the outstanding problems of poor motion flexibility and poor terrain adaptability of conventional mobile robots in unstructured environments, a multi-vehicle modular articulated mobile robot capable of adapting to complex and variable obstacle terrain was developed by designing and introducing a flexible articulation device. By constructing a kinematic model of the single body module of the robot, integrating the motion constraint relations among the modules, and establishing the overall robot attitude equations, we propose a robot soft motion control method. Based on the analysis of robot motion characteristics under special obstacle terrain, the relationship model between obstacle parameters and robot pose is constructed, and the correction strategy under unilateral unstable motion state is proposed through the analysis of robot motion state under unilateral unstable condition. Theoretical analysis and experimental results show that the robot has good motion flexibility and complex terrain adaptability.

Solubilities of gimeracil (form P) in aqueous co-solvent mixtures of isopropanol, N,N-dimethylformamide (DMF), ethylene glycol (EG) and dimethylsulfoxide (DMSO) were investigated via the isothermal dissolution equilibrium method at (283.15–328.15) K under ambient pressure p = 101.2 kPa. Experimental solubility was increased with increasing temperature and mass fraction of each co-solvent. The largest solubility was found in neat co-solvents. The solids equilibrated with liquid phase were characterized by X-ray power diffraction, indicating no polymorphic transformation, solvate formation or crystal transition according to the spectral data. The Jouyban-Acree model was adopted to correlate the obtained solubility. The highest RAD and RMSD values were, respectively, 2.61 × 10−2 and 14.96 × 10−4. Quantitative values for the local mole fraction of DMF (EG, DMSO or isopropanol) and water around gimeracil (form P) were acquired by using the Inverse Kirkwood–Buff integrals method. The preferential solvation parameters for isopropanol were positive in the isopropanol mixtures in intermediate and isopropanol-rich compositions, which indicated that gimeracil (form P) was preferentially solvated by isopropanol. Gimeracil (form P) could act mainly as a Lewis acid interacting with proton-acceptor functional group of isopropanol. Within the same region, gimeracil (form P) was not preferentially solvated by DMF, EG and DMSO. Furthermore, the method of linear solvation energy relationships was performed with a suitable combination of solvent polarity descriptors to explain the nature of intermolecular interactions resulting in the solubility variation in the co-solvent mixtures.

The mole fraction solubility of bioactive iminodibenzyl in aqueous co-solvent mixtures of ethanol, ethylene glycol (EG), dimethyl sulfoxide (DMSO) and isopropanol was examined by the saturation shake-flask method over the temperature range from 283.15 K to 328.15 K at pressure of 101.2 kPa. The experimental solubility increased with increasing temperature at a given co-solvent composition and decreased with the increasing mass fraction of water in each binary system. The maximum solubility was found in pure co-solvent. Given the same temperature and mass fraction of the co-solvent, the solubility of iminodibenzyl was greater in (DMSO + water) than in the other three co-solvent systems. The solid crystal examples of iminodibenzyl was tested by X-ray power diffraction showing no polymorphic transformation, solvate formation or crystal transition during entire experiments. The Jouyban-Acree model was employed to correlate the measured solubility. The calculated data were in alignment to measured values and RAD and RMSD data were no more than 3.08% and 10.37 × 10−4, respectively. Furthermore, quantitative values for the local mole fraction of ethanol (EG, DMSO or isopropanol) and water around the iminodibenzyl were acquired by using the Inverse Kirkwood–Buff integrals method. The preferential solvation parameters for ethanol, EG, DMSO or isopropanol were positive in the four co-solvent mixtures in intermediate and co-solvent-rich compositions, which indicated that iminodibenzyl was preferentially solvated by the co-solvent. iminodibenzyl could act mainly as a Lewis acid interacting with proton-acceptor functional groups of the co-solvents.

Experimental measurement of drug quinocetone solubility in water-co-solvent mixtures of ethanol, isopropanol, dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) were determined by the static equilibrium method at temperature range of (283.15–328.15) K under ambient condition (101.2 kPa). The solid phase equilibrated with liquor was examined by X-ray power diffraction, resulting in no polymorphic transformation, solvate formation or crystal transition compared to the raw material. Quantitative knowledge about the solvent effect on the solubility was obtained with the help of linear solvation energy relationships in the terms of dipolarity-polarizability, hydrogen-bond donor and acceptor ability, and cavity term of mixtures. The preferential solvation was investigated from their thermodynamic solution properties by means of the inverse Kirkwood-Buff integrals. The preferential solvation parameters (δx1,3) for ethanol, isopropanol, DMSO or DMF were negative in the four co-solvent mixtures with water-rich compositions, which indicated that quinocetone was preferentially solvated by water. Temperature has a little effect on the preferential solvation magnitudes for the ethanol and isopropanol mixtures. The higher solvation by water could be explained in terms of the higher acidic behavior of the solvents interacting with the Lewis basic groups of the quinocetone. In addition, thermodynamic co-solvency models including the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model and Modified Apelblat-Jouyban-Acree model were employed to describe the solubility of this drug obtaining average relative deviations lower than 2.14% and root-mean-square deviations lower than 1.75 × 10−4 for correlative studies. The standard dissolution enthalpies of quinocetone in the solvent mixtures were positive, demonstrating that the dissolution process of quinocetone was endothermic.

The equilibrium solubility data of allopurinol in aqueous co-solvent mixtures of ethanol, isopropanol, N,N-dimethylformamide (DMF) and 1-methyl-2-pyrrolidone (NMP) was experimentally determined by a saturation shake-flask method within the temperatures from 293.15 K to 333.15 K under atmospheric pressure. It was found that in the (DMF + water) and (NMP + water) systems, the solubilities of allopurinol increased with increasing temperature and DMF (NMP) composition. However in the (ethanol + water) and (isopropanol + water) systems, they increased at first and then decreased with an increase in mass fractions of ethanol and isopropanol. The determined solubility values were correlated by using the Jouyban-Acree, van’t Hoff-Jouyban-Acree and Apelblat-Jouyban-Acree models obtaining average relative deviations lower than 6.84% for correlative studies. Preferential solvation parameters of allopurinol were derived by means of the inverse Kirkwood-Buff integrals method. There were significant different behaviours of the allopurinol between in ethanol (isopropanol) + water and DMF (NMP) + water mixtures. The preferential solvation parameter δx1,3 by co-solvent is positive in the regions of 0.25

The equilibrium solubilities of chlorhexidine in four solvent mixtures of methanol (1) + water (2), ethanol (1) + water (2), DMF (1) + water (2) and 1,4-dioxane (1) + w water (2) at temperature range from (278.15 to 318.15) K were reported. At the same composition of methanol, ethanol, DMF or 1,4-dioxane and temperature, the mole fraction solubility of chlorhexidine was highest in DMF (1) + w water (2) mixtures, and lowest in ethanol (1) + w water (2) mixtures. By using the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model, chlorhexidine solubility was well correlated obtaining RAD lower than 1.69% and RMSD lower than 0.87 × 10−4. The dissolution process of chlorhexidine in solvent solutions was endothermic for the dissolution process. To study the solvent effect, solubility data were correlated to KAT parameters and cavity term on the basis of linear solvation energy relationships concept. Results indicate the key effect of cavity term and π∗ in aqueous methanol and ethanol mixtures; cavity term in aqueous DMF mixtures; and cavity term, β and π∗ in aqueous 1,4-dioxan mixtures. Quantitative values for the local mole fraction of methanol (ethanol, DMF or 1,4-dioxane) and water around the chlorhexidine were computed by using the IKBI method applied to the determined solubility data. Chlorhexidine was preferentially solvated by water for the four solvent mixtures in water-rich compositions; while in intermediate and co-solvent-rich composition for ethanol (DMF, 1,4-dioxane) (1) + w water (2) mixtures, chlorhexidine is preferentially solvated by the co-solvent. The preferential solvation magnitude of chlorhexidine was highest in 1,4-dioxane mixtures than in the other three solvent mixtures.

Objective This study aims to demonstrate clinicopathological characteristics and immunohistopathological phenotypes of pseudomyxoma peritonei (PMP) originated from ovaries. Methods The primary origin of PMP was explored by reviewing H&E sections retrospectively and performing a series of immunohistochemical staining on CK7, CK20, CDX2, CEA, Villin, SATB2, CA125, ER, PR, and MUC. Results Among 310 PMP patients, a few originated from extra-appendix, whereas eight cases were of ovarian origin (2.6%), including three teratoma-associated ovarian mucinous tumors and five primary ovarian mucinous tumors with spontaneous or iatrogenic rupture, respectively. Most peritoneal metastases were acellular mucin or low-grade mucinous carcinoma peritonei (6/8, 75%), while the rest were high-grade mucinous carcinoma peritonei (2/8, 25%). Tumors were positive for CK20, CDX2, CEA, and Villin. SATB2 was specifically diffuse positive in teratoma-associated ovarian mucinous tumors, and negative in primary ovarian mucinous tumors. Differential expression of MUC was observed in these tumors. Conclusion PMP of ovarian origin is extremely rare. The precise diagnosis requires serial sections of the appendix or suspicious tissue to exclude appendiceal mucinous neoplasms, as well as comprehensive analysis of clinical features, surgical findings, histopathological characteristics, and immunohistochemistry on specific biomarkers.

The D-tryptophan solubility in aqueous solutions of methanol, ethanol, isopropanol and N,N-dimethylformamide (DMF) was measured by the saturation shake-flask method at temperatures ranging from 283.15 K to 333.15 K. The maximum solubility was found in water for alcohol (1) + water (2) mixtures, and in neat DMF for DMF (1) + water (2) mixture. When the same temperature and mass fraction of the water is given, the highest mole fraction solubility of D-tryptophan was found in (DMF + water). The solid phases were tested by X-ray powder diffraction (XPRD) showing no polymorphic transformation, solvate formation or crystal transition. Three solubility models, i.e. the Jouyban-Acree, van’t Hoff-Jouyban-Acree and Apelblat-Jouyban-Acree were employed to correlate the experimental solubility values so as to obtain thermodynamic parameters. The RAD and RMSD data were no more than 1.65% and 9.40 × 10−5, respectively. Linear solvation energy relationship analysis based on Kamlet-Taft parameters indicated that the variation of D-tryptophan solubility depended on π∗ for methanol (ethanol, isopropanol) (1) + water (2), and cavity term for DMF (1) + water (2). The preferential solvation parameters (δx1,3) for methanol, ethanol, isopropanol and DMF derived by means of the inverse Kirkwood–Buff integrals were negative in the four solvent mixtures with intermediate and alcohol-rich compositions, which indicated that D-tryptophan was preferentially solvated by water. The higher solvation by water could be explained in terms of the higher acidic behaviour of the solvents interacting with the Lewis basic groups of the D-tryptophan. However D-tryptophan is preferentially solvated neither by water nor by DMF in DMF + water mixture.

The mole fraction solubility of 6-chloropurine in aqueous mixtures of methanol, ethanol, N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) was measured by a saturation shake-flask method over the temperature range of (283.15–328.15) K at pressure of 101.2 kPa. The solubility of 6-chloropurine increased positively with increasing temperature at a given solvent composition and decreased with increasing mass fraction of water in each binary system. The maximum solubility was found in neat methanol, ethanol, DMF and DMA. Given the same temperature and mass fraction of the organic solvent, the solubility of 6-chloropurine was greater in (DMF + water) than in the other three solvent mixtures. The X-ray power diffraction (XPRD) analysis showed that no polymorphic transformation, solvate formation or crystal transition took place during the experiments. Linear solvation energy relationships concept was used to describe the variation in the solubility based on the solvent effect. The preferential solvation parameters were derived from their thermodynamic solution properties using inverse Kirkwood–Buff integrals. The preferential solvation parameters (δx1,3) for methanol, ethanol, DMF and DMA were negative in the four solvent mixtures with water-rich compositions, which indicated that 6-chloropurine was preferentially solvated by water. Temperature has little effect on the preferential solvation magnitudes. The higher solvation by water could be explained in terms of the higher acidic behavior of the solvents interacting with the Lewis basic groups of the 6-chloropurine. Furthermore, several mathematical cosolvency models were adopted to correlate the measured solubility values. The relative average deviation and root-mean-square deviation were no more than 2.36% and 1.026 × 10−3, respectively.

A numerical study was performed of the resonance behavior of a reverse-flow reactor that conducts methane and propane binary-mixture catalytic oxidation. A one-dimensional heterogeneous model was used. A resonance response occurs when the periodic inlet concentration variation cycle is the odd part of the flow-reversal cycle, which results in temperature excursion and a sharp increasing in maximum temperature within the reactor. Decreasing in average temperature implies thermal stability of the reactor is impaired. Temperature variation in the reactor is induced by both inlet concentration variation and flow-reversal operation, which may contain low frequency variation. Such resonance behavior is attributed to the breakdown of spatial and temporal symmetry of the reactor. Thus, ways to compensate such asymmetry can be used to maintain stable reactor operation, including adjusting the initial phase difference between the flow-reversal cycle and the inlet concentration variation cycle or the addition of supplemental fuel.

The combustion behaviour of solid fuels – for example, coke and biomass char – is an important consideration in iron ore sintering as it determines heat availability for the melt formation process. This behaviour is influenced by the presence of an adhering layer of fine material around the fuel particles. In this study, analytical results for the combustion of single granulated fuel particles – applicable to all Thiele modulus (ϕh) values – are presented. For the conversion of an isothermal carbon particle, the conversion parameter α is found to depend on ϕh and the effectiveness factor ηh. For ϕh 9, α approaches ηh/3. The relationship between α and ηh is not altered by the presence of an adhering layer. However, at high temperatures and for reactive fuels, an adhering layer influences the combustion rate significantly. The fuel combustion process in iron ore sintering can be viewed as occurring in three regimes depending on factors such as fuel size, reactivity and temperature. To investigate the effect of fuel properties on sintering performance, the developed combustion model is integrated into a 2D iron ore sintering model. Good comparisons are obtained between model results and experimental data from laboratory sintering tests. In the study of fuel types, model results indicate that when biomass char replaced coke there was significant lowering of flame front temperature and combustion efficiency, while the speed of the flame front down the bed accelerated. These changes can be explained by the higher reactivity of the biomass char and its physical properties which influence the granulation process – resulting in changes in the thickness of the adhering layer and combustion behaviour. The flow-on effect of this on sintering performance is consistent with reported experimental results by other researchers.

The preferential solvation parameters (δx 1,3) 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 δx 1,3 vary non-linearly with the solvent (1) proportion in the two solvent mixtures. For the ethanol (1) + ethyl acetate (2) system, the values of δx 1,3 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 δx 1,3 are positive in ethyl acetate-rich mixtures and in intermediate compositions, but negative in isopropanol-rich mixtures. The δx 1,3 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 x 1 = 0.40–0.45 for the two solvent mixtures.

Equilibrium solubility data of nitroxoline in mixed solvents of (ethyl acetate + methanol), (ethyl acetate + ethanol), (ethyl acetate + n-propanol) and (ethyl acetate + isopropanol) were obtained experimentally by using the static method within the temperature range from (278.15 to 313.15) K under atmospheric pressure of 101.1 kPa. The mole fraction solubility of nitroxoline increased with increasing temperature and mass fraction of ethyl acetate. The obtained solubility data were mathematically represented by using five cosolvency models, including Jouyban–Acree model, van’t Hoff-Jouyban-Acree model, Apelblat-Jouyban-Acree model, Ma model, and Sun model. The maximum value of relative average deviation was 1.64 × 10−2, and root-mean-square deviation, 0.77 × 10−4. The dissolution process of nitroxoline in these mixed solvents was endothermic. The preferential solvation parameters were derived from their thermodynamic solution properties via the method of inverse Kirkwood–Buff integrals. The preferential solvation parameters for nitroxoline (δx1,3) were positive in intermediate compositions and ethyl acetate-rich mixtures but negative in alcohol-rich compositions. In the regions with intermediate composition, the preferential solvation magnitude of nitroxoline by the ethyl acetate is higher in {ethyl acetate (1) + ethanol (2)} mixtures than in the other solvent mixtures at 298.15 K. The higher solvation by ethyl acetate in intermediate compositions and in ethyl acetate-rich mixtures could be explained in terms of the higher basic behaviour of ethyl acetate interacting with the Lewis acidic groups of the nitroxoline.

The preferential solvation parameters ( δx 1,3 ) 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 δx 1,3 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 δx 1,3 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 x 1 x 1 x 1 x 1 tert -butanol (1) + water (2)} mixtures and the other four co-solvent mixtures were found.

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.

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.

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.

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.

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 Janeck 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.

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.

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

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.