反气相色谱法与Hansen溶解度参数法测定聚乙烯醇溶解度参数及相关热力学性质

采用反气相色谱（IGC）法,以聚乙烯醇（PVA）为固定相,脂肪族、芳香族、醇、酮及卤代烃5类18种化合物为探针分子,研究PVA的溶解性质并获得了PVA在383.15～423.15 K范围内的溶解度参数（δ₂）及相关热力学性质,并与Hansen溶解度参数法（HSP）测得的溶解度参数（δ_T）进行比较。结果表明,5类溶剂对PVA溶解能力的趋势为酮类 >醇类 >卤代烃、芳香类、脂肪族类>脂环族,卤代烃、芳香类和脂肪族类溶剂的溶解能力相似;在测试温度范围内PVA的δ₂随温度升高而增加;采用IGC法外推出室温（298.15 K）下PVA的δ₂为27.69 （J/cm³）^0.5,与HSP法测得室温下PVA的δ_T（27.77 （J/cm³）^0.5）一致。PVA溶解度参数及相关热力学参数的研究为其应用及相关研究提供了定量依据。     

Equilibrium solubility of 6-propyl-2-thiouracil in nine pure solvents: Determination,correlation, Hansen solubility parameter and thermodynamic properties

Investigation upon the solid–liquid equilibrium on solubility data of 6-propyl-2-thiouracil (PLT) in pure organic solvents is essential for separation and purifying in industry process. In this work, PLT solubility in nine neat solvents was experimentally determined at 278.15 K–323.15 K under P = 0.1 MPa. These selected solvents were tetrahydrofuran(THF), acetone, acetonitrile,1-butanol,1-pentanol, 2-butanol, methyl acetate, ethyl acetate,1-propyl acetate, respectively. Experiment results showed that solubility was consistent with temperature and decreased according to the order: THF > acetone>1-butanol≈1-pentanol> 2-butanol > methyl acetate > ethyl acetate>1-propyl acetate > acetonitrile. Solvent effect and Hansen solubility parameter (HSP) were incited to explain dissolution rule on solute. Four thermodynamic models (modi?ed Apelblat model, Van't model, λh model and NRTL model) were adopted to correlate PLT solubility and provide good correlations on basis of RD, ARD and RMSD. In addition, thermodynamic properties (ΔH°, ΔS° and ΔG°) of PLT dissolution process in pure solvents were discussed and proved to be endothermic, entropically driven and non-spontaneous process.     

Elastomer swelling and Hansen solubility parameters

The prediction of how much an elastomer swells in contact with a given solvent is important in many industrial processes. In this article, Hansen solubility parameters (HSP) of two EPDM elastomers and one FKM elastomer were determined before vulcanisation by correlating solubility in those solvents that fully dissolved the polymers. These values were then used to generate plots of solvent swelling after the same elastomers were vulcanised. HSP correlations were also established for the same vulcanised elastomers at different levels of swelling. This makes its possible to predict the swelling of the elastomers studied in contact with many untested solvents.     

Estimation of solubility and interaction parameters in binary liquid mixtures by reversed-flow gas chroamtography

Summary A new method, called reversed-flow gas chromatography, is presented for the measurement of the gaseous equilibrium concentrations of all the components under study, both in the pure state and in binary liquid mixtures. From the equilibrium concentrations, activities, activity coefficients and volume fraction activity coefficients were determined. Using various empirical equations relating activity with the molecular interactions between the components of a binary liquid mixture, the solubility parameters of ethanol, 1-propanol, acetone and methylethylketone in water were calculated. The total interaction parameters and the partial contributions of the dispersion, orientation and residue forces on the van der Waals attraction between the organic compounds and water were also computed. The variation of the interaction parameters with the composition of organic component in the binary mixture was investigated. The successful application of reversed-flow gas chromatography to the estimation of polymer solubility parameters is also reported. Finally, the solubility parameters found by the present method are compared with those determined by other techniques or calculated theoretically.     

Deferiprone solubility in some non-aqueous mono-solvents at different temperatures: experimental data and thermodynamic modelling

The solubility of deferiprone (DFP) in five organic solvents including ethyl acetate, chloroform, acetonitrile, 1,4-dioxane and dichloromethane was investigated by the flask-shake method under atmospheric pressure at temperatures ranging from 293.15 to 313.15 K. In general, the solubility (mol L^–1) obeyed the following order from high to low in different mono-solvents: dichloromethane > chloroform > acetonitrile > 1,4-dioxane > ethyl acetate. The solubility of DFP in the mono-solvents increased with a rise of temperature. The solubility data were successfully correlated with the van’t Hoff equation. The generated data in this work and the previously published data were used to calculate the thermodynamic parameters of the system using the modified van’t Hoff equation, and the derived thermodynamic properties were correlated using Abraham solvation parameters.     

Measurement and thermodynamic modeling of Np(V) solubility in aqueous K2CO3 solutions to high concentrations

The solubility of Np(V) solids was studied in 0.01 to 6.38 mol-Kg^-1 ₂CO₃ solutions. Two series of experiments were conducted from undersaturation using NpO₂OH(s) or KNpO₂CO₃(s) as the starting solid. The Np(V) solid phases observed at steady state are KNpO₂CO₃(s) and K₃NpO₂(CO₃)₂(s). The activity coefficient formalism of Pitzer was used to obtain a thermodynamic interpretation of these data, including the solubility constants: To model these data, we propose values for several binary and ternary ion interaction parameters among the carbonate ion, potassium ion, and the neptunyl triscarbonato ion. With these new parameters, the thermodynamic data base for Np(V) solubility in concentrated aqueous solutions has been extended to the NaK-C1-C1O₄-CO₃-H-OH-H₂O system.     

Solubility Determination,Hansen Solubility Parameters and Thermodynamic Evaluation of Thymoquinone in (Isopropanol + Water) Compositions

This article studies the solubility, Hansen solubility parameters (HSPs), and thermodynamic behavior of a naturally-derived bioactive thymoquinone (TQ) in different binary combinations of isopropanol (IPA) and water (H₂O). The mole fraction solubilities (x₃) of TQ in various (IPA + H₂O) compositions are measured at 298.2–318.2 K and 0.1 MPa. The HSPs of TQ, neat IPA, neat H₂O, and binary (IPA + H₂O) compositions free of TQ are also determined. The x₃ data of TQ are regressed by van’t Hoff, Apelblat, Yalkowsky–Roseman, Buchowski–Ksiazczak λh, Jouyban–Acree, and Jouyban–Acree–van’t Hoff models. The maximum and minimum x₃ values of TQ are recorded in neat IPA (7.63 × 10⁻² at 318.2 K) and neat H₂O (8.25 × 10⁻⁵ at 298.2 K), respectively. The solubility of TQ is recorded as increasing with the rise in temperature and IPA mass fraction in all (IPA + H₂O) mixtures, including pure IPA and pure H₂O. The HSP of TQ is similar to that of pure IPA, suggesting the great potential of IPA in TQ solubilization. The maximum molecular solute-solvent interactions are found in TQ-IPA compared to TQ-H₂O. A thermodynamic study indicates an endothermic and entropy-driven dissolution of TQ in all (IPA + H₂O) mixtures, including pure IPA and pure H₂O.     

An evaluation of thermodynamic models for the prediction of drug and drug-like molecule solubility in organic solvents

Prediction of solubility of active pharmaceutical ingredients (API) in different solvents is one of the main issue for crystallization process design. Experimental determination is not always possible because of the small amount of product available in the early stages of a drug development. Thus, one interesting perspective is the use of thermodynamic models, which are usually employed for predicting the activity coefficients in case of Vapour-Liquid equilibria or Liquid-Liquid equilibria (VLE or LLE). The choice of the best thermodynamic model for Solid-Liquid equilibria (SLE) is not an easy task as most of them are not meant particularly for this. In this paper, several models are tested for the solubility prediction of five drugs or drug-like molecules: Ibuprofen, Acetaminophen, Benzoic acid, Salicylic acid and 4-aminobenzoic acid, and another molecule, anthracene, a rather simple molecule. The performance of predictive (UNIFAC, UNIFAC mod., COSMO-SAC) and semi-predictive (NRTL-SAC) models are compared and discussed according to the functional groups of the molecules and the selected solvents. Moreover, the model errors caused by solid state property uncertainties are taken into account. These errors are indeed not negligible when accurate quantitative predictions want to be performed. It was found that UNIFAC models give the best results and could be an useful method for rapid solubility estimations of an API in various solvents. This model achieves the order of magnitude of the experimental solubility and can predict in which solvents the drug will be very soluble, soluble or not soluble. In addition, predictions obtained with NRTL-SAC model are also in good agreement with the experiments, but in that case the relevance of the results is strongly dependent on the model parameters regressed from solubility data in single and mixed solvents. However, this is a very interesting model for quick estimations like UNIFAC models. Finally, COSMO-SAC needs more developments to increase its accuracy especially when hydrogen bonding is involved. In that case, the predicted solubility is always overestimated from two to three orders of magnitude. Considering the use of the most accurate equilibrium equation involving the ΔC_p term, no benefits were found for drug predictions as the models are still too inaccurate. However, in function of the molecules and their solid thermodynamic properties, the ΔC_p term can be neglected and will not have a great impact on the results.     

Experimental and thermodynamic analysis on the solubility of valsartan in ethyl acetate + (butanone,isopropyl ether) binary solvent mixtures (from 278.15 to 323.15 K)

The solubility of valsartan in ethyl acetate + (butanone, isopropyl ether) binary solvent mixtures was measured at temperatures T = 278.15–323.15 K and pressure p = 0.1 MPa with a laser monitoring dynamic technique by a synthetic method. The experimental data were regressed by the modified Apelblat equation, the general single model and the hybrid model. The experimental data are well correlated with the above models because the mean deviations (MDs) are less than 3.79%. The mole fraction solubility of valsartan increases with increase in temperature and enrichment in butanone content, while it decreases with increased mole fraction of isopropyl ether at constant temperature. In addition, thermodynamic studies, including Gibbs energy, entropy and enthalpy, were calculated by van’t Hoff analysis. The results showed that the dissolution of valsartan in mixed solvents is endothermic, spontaneous and entropy-driven.     

Solubility of antioxidant 1010 in pure alkanols

In an equilibrium vessel, the solubility of antioxidant 1010 in pure alkanols was measured in the temperature range from 283.15 K to 343.15 K using a method in which an excess amount of solute was equilibrated with the alkanol solution. The liquid concentrations of the investigated antioxidant 1010 in the saturated solution were analyzed by UV-spectrometry. The solubility data have been correlated as functions of the temperature. Activity coefficients for antioxidant 1010 have been calculated by means of the Wilson, NRTL and UNIQUAC equations and with them were correlated solubility data that were compared with the experimental ones. The best correlation of the solubility data has been obtained by the Wilson equation, by which the average root-mean-square deviation of temperature for the seven systems is 0.62 K.     

Experimental measurement and modeling of solubility of LiBr and LiNO3 in methanol, ethanol, 1-propanol, 2-propanol and 1-butanol

The solubility of lithium bromide and lithium nitrate in solvents methanol, ethanol, 1-propanol, 2-propanol and 1-butanol were measured in the range between 298.15 and 338.15 K using an analytical gravimetric method. An empirical equation was used to fit the experimental solubilities and the Pitzer model with inclusion of Archer's ionic strength was used for the calculation of osmotic coefficients. The experimental data of system pressures (p) for the correlation of LiBr + ethanol, LiBr + 2-propanol at T (298.15-333.15 K) and LiNO₃ + ethanol at T (298.15-323.15 K) were obtained from published literatures. Moreover, the parameters of the Pitzer model were re-correlated and were used to predict mean ion activity coefficients. A procedure was also presented to predict the solubility products of salts in pure organic solvent.     

Solubility of tridecanedioic acid in pure solvent systems: An experimental and computational study

Solubility has been extensively investigated by the phase equilibria approach at the mesoscale level, but its origin on the molecular and electronic levels is poorly understood. This study explored the solubility behaviour of crystalline solid in selected pure solvents with various functional groups by using both phase equilibria and molecular modelling methods. The model compound tridecanedioic acid (TDDA) solubility in methanol, ethanol, acetic acid, acetone, and ethyl acetate was determined from T = (283.15 to 323.15) K by a static method. It was found that almost all solutions studied exhibit non-ideal behaviour and deviate positively from Raoult’s law indicating the important role of homo-molecules interactions. Thermodynamic analyses of solution suggest that both enthalpy and entropy of solution govern the dissolution process. Computational studies on solubility behaviour were performed by using both density functional theory (DFT) calculations and molecular dynamic (MD) simulations. The results conclude that the (solute + solvent) interaction is not the only factor determining solubility, and (solvent + solvent) interaction also plays an important role. The simulated results are found to be qualitatively consistent with experimental values. Finally, solubility values were correlated by the empirically modified Apelblat equation and two local composition models of Wilson and NRTL.     

Role of Hansen solubility parameters in solid phase extraction

The sorbent–eluent systems combined from eight polymeric sorbents and seven solvents as eluents were used for the extraction of phenol and its oxidation products from water samples. The individual interactions between sorbents, eluents and analytes were characterized by Hansen solubility parameters. Principal components analysis (PCA) was used for revealing the dominant interactions (dispersive, polar, and hydrogen bonding type) in sorbent–analyte–eluent systems. The importance of solubility parameters was also determined by a novel procedure based on sum of ranking differences (SRD). Although PCA and ranking by SRD are based on different principles and calculations, they have provided very similar results. The recovery in a given system has been predicted from the magnitudes of mutual interactions (sorbent–analyte, sorbent–eluent, analyte–eluent) by multiple linear regression.     

Determination of the solubility, dissolution enthalpy and entropy of Deflazacort in different solvents

The solubility of Deflazacort in four solvents, acetone, ethyl acetate, ethanol and 2-propanol, was measured at temperatures ranging from 293.15 K to 348.15 K at atmospheric pressure using Laser Monitoring Technique. The solubility data were correlated by the modified Apelblat model. Then the dissolution enthalpy and entropy of Deflazacort were predicted from the solubility data using van’t Hoff equation. In this study, it should be concluded that the viscosity and surface tension of solvents affect the solubility behavior, dissolution enthalpy and entropy of Deflazacort in different solvents.     

Further calculations on solubility of dipyrone in some binary solvent mixtures at various temperatures

The recently reported solubility data of dipyrone in binary solvent mixtures of {ethanol + water}, {methanol + ethanol} and {methanol + 1-propanol} at various temperatures have been used to report further numerical results based on the Jouyban–Acree model.     

The solubility of barite and celestite in sodium sulfate: Evaluation of thermodynamic data

The solubilities of barite [BaSO₄(c)] and celestite [SrSO₄(c)] in Na₂SO₄ were studied and found to be significantly lower than the experimental values reported in the literature. Our new solubility data are in excellent agreement with the predictions of ion interaction models, which have previously been parameterized primarily from solubility data obtained in chloride media. Our solubility data were analyzed both in terms of aqueous thermodynamic models that included ion association species and in terms of ion interaction models that did not require the explicit recognition of such species. In the case of SrSO₄, although both ion association and ion interaction models can accurately model our solubility data, the ion interaction approach is preferred because it is easier to extend to higher concentrations. In the case of BaSO₄, the aqueous ion interactions appear to be stronger than those for SrSO₄, and so the explicit recognition of a BaSO₄(aq) ion association species is preferred. The logarithms of the thermodynamic solubility products (log K _sp ) for celestite and barite were –6.62±0.02 and –10.05±0.05, respectively. When the data were analyzed using models that include ion association species, the logarithms of the thermodynamic equilibrium constants for the SrSO₄(aq) and BaSO₄(aq) association reactions were 1.86±0.03 and 2.72±0.09, respectively.     

Effect of sulfonic group on solubility parameters and solubility behavior of poly(2,6‐dimethyl‐1,4‐phenylene oxide)

An investigation on the effect of sulfonic group on solubility parameters and solubility behavior of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) is presented. Sulfonated PPO (SPPO) was prepared using chlorosulfonic acid as a sulfonating agent. The structure of SPPO was confirmed by FT‐IR, and the ion exchange capacity (IEC) of SPPO was accurately determined by conductometric titration and ¹H‐NMR. The three‐dimensional solubility parameters of SPPO defined by Hansen were estimated by group contribution, and this approach was used to obtain the three coordinates of a solubility parameter in terms of: a dispersion part δ_d, a polar part δ_p and a hydrogen bonding part δ_h. The theoretical predications of solubility behavior were characterized using “soluble sphere” in three‐dimensional space. The estimated results were in accordance with the solubility experiments in different solvents. Copyright © 2006 John Wiley & Sons, Ltd.