Temperature-dependence of the solubility of some acetanilide derivatives in several organic and aqueous solvents

The thermodynamic functions free energy, enthalpy, and entropy of solution, were evaluated from the solubility data of acetanilide, acetaminophen, and phenacetin, determined at several temperatures in water, octanol, isopropyl myristate, and chloroform. These three organic solvents mutually saturated with water, and finally, in cyclohexane. In the aqueous media, the solubility was determined at pH 7.4 and ionic strength 0.15?mol?L^?1. The excess free energy and the activity coefficients of the solutes were also determined. The solubility for acetanilide and phenacetin was higher in organic media such as octanol and chloroform than is those obtained in the aqueous media and cyclohexane, while for acetaminophen the solubility was higher in octanol than those obtained in the other solvents.     

Solubility of drug-like molecules in pure organic solvents with the CPA EoS

Solubility data in different solvents are an important issue for separation processes involving complex molecules such as natural products and pharmaceutical drugs. Nonetheless, solubility data are in general scarce and difficult to obtain, and so models are important tools to generate the necessary estimates.Different correlative, statistical and thermodynamic models have been proposed to evaluate solubilities. From these, the more theoretically sound thermodynamic models allow to generate estimates at broader temperature, pressure and composition conditions while using a smaller amount of experimental information. Among these, the cubic-plus-association equation of state that combines the simplicity and robustness of a cubic equation of state with the Wertheim's association contribution has been under attention. In this work, this EoS is for the first time proposed to model organic phase solubilities of drug-like molecules in a wide range of temperatures.Solubilities of acetanilide, acetylsalicylic acid, adipic acid, ascorbic acid, hydroquinone, ibuprofen, paracetamol and stearic acid were estimated in alcohols, ketones, alkanes, esters, acids, aromatics, chlorinated solvents, as well as in other common solvents. The hydrogen bonding behaviour was explicitly accounted for with each associating group being treated individually, as well as multiple group substitutions.Accurate correlations were obtained using a single binary interaction parameter (global AAD of 24.2%), while considering the complexity of the studied systems predictions were generally also satisfactory.     

Experimental analysis and thermodynamic modelling of Nitroxynil solubility in pure solvent and binary solvent

Nitroxynil(NIT) is a commonly used anti-liver fluke drug for cattle and sheep, Its solubility is closely related to its preparation. In this work, the molar solubility of NIT in nine pure solvents (methanol, ethanol, 1,2-propanediolethyl, isopropanol, ethyl acetate, acetonitrile, n-butanol, phemethylol) and two kinds of binary mixtures with different ratio(ethanol + phemethylol; ethanol + acetonitrile) was determined by shake flask method over the temperature from 278.15 ～ 323.15 K at atmosphere pressure. Results show that the solubility of NIT in all tested solvents was increased with raised temperature. In mono-solvents, the mole fraction solubility of NIT was highest in phemethylol and the solubility order is: phemethylol > acetonitrile > ethyl acetate > methanol > n-butanol > ethanol > 1,2-propanediolethyl > isopropanol > water. In binary solvents, the mole fraction solubility increased with increasing ratio of phemethylol/acetonitrile. In mono-solvents, the modified Apelblat equation, λh equation, Van't Hoff model were applied to correlate the solubility data. In binary solvents, the modified Apelblat equation, λh equation, GSM model and Jouyban-Acree model were to correlate the solubility data. Solubility order of NIT in nine pure solvent and two binary solvent systems were analysed by using the Hansen solubility parameter (HSP). Activity coefficient was to access the solute–solvent molecular interactions. In addition, the dissolution of NIT is an endothermic and entropy-friendly process, since thermodynamic parameters such as enthalpy, entropy, and apparent standard Gibbs free energy are all greater than zero. The results will supply some essential data on recrystallization process, purification and formulation development of NIT in pharmaceutical applications.     

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.     

Pitzer混合参数对HCl-NaCl-H_2O体系溶解度预测的影响

电解质溶液的理论 (或模型 ),在实际的化学和化工过程中有着极其广泛的应用 ,其中 Pitzer模型 [1]就是一个范例 .应用此模型 ,对世界上四大水盐体系中组分溶解度的预测都获得成功 [2－ 4].但该模型对 HCl- LiCl- MgCl2- H2O四元体系在 0和 40℃时的溶解度预测结果和实验结果的偏差较大 [5].为寻找引起偏差的原因 ,笔者分别对 Pitzer方程中各个参数对溶解度预测的敏感性进行了研究 .我们在前文中分别报导了含 HCl四元水盐体系中 ,当 HCl的浓度高于 16.00 mol· kg－ 1时 ,HCl的 Pitzer参数的获得过程 ,及将优化后的参数应用于 HCl- M…     

Pitzer混合参数对HCl-NaCl-H2O体系溶解度预测的影响

This paper reports the results of solubility calculation of the phase system HCl NaCl H2O at 25 ℃ when θHNa (interactions of two species with the same charge) and ΨHNaCl (interactions of three species) were changed by ＋10％ and －10％. The results indicated that the effects of the two kinds of interactions on the calculated solubility of the system were regular. The calculated solubilities of the system did not vary while the two interactions were increased and decreased simultaneously. The solubility data of the system changed greatly as one interaction was increased and the other decreased. This study is significant for the chemical technology of salting out salts from the water salt system.     

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.     

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.     

Considerations for the automated collection of thermodynamic data in gas chromatography

Thermodynamic modeling of retention times in gas chromatography depends on the accurate estimation of thermodynamic parameters. Previous research has used manual injections of samples with coinjection of a dead time marker to obtain accurate measurements of the retention factor of analytes. Ideally this process would be automated. Herein an approach is presented by which thermodynamic parameters can be estimated both autonomously and accurately. This method also allows for a consistent estimation of thermodynamic parameters regardless of factors such as data system delays and the nature of the void time marker employed. Ignoring these factors can lead to significant errors in the prediction of retention times when using thermodynamic models.     

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.     

(Liquid + liquid) equilibrium in binary systems of isomeric C8 aliphatic monoethers with acetonitrile and its interpretation by the COSMO-SAC model

The (liquid + liquid) solubility curves have been determined by a synthetic method for six binary mixtures of [acetonitrile + {heptyl methyl ether CH₃OⁿC₇H₁₅, or ethyl hexyl ether C₂H₅OⁿC₆H₁₃, or pentyl propyl ether ⁿC₃H₇OⁿC₅H₁₁, or isopentyl propyl ether ⁿC₃H₇Oⁱ C₅H₁₁, or dibutyl ether ⁿC₄H₉OⁿC₄H₉, or butyl isobutyl ether ⁿC₄H₉OⁱC₄H₉}]. The possibility of the COSMO-SAC model to account for the thermodynamic differences between these systems has been tested and the discussion on the influence of screening charge of ethers on the system properties was undertaken.     

Representation of activity coefficients of fundamental biochemicals in water by the UNIFAC model

The assignment of UNIFAC parameters has been newly examined to represent the activity coefficients of fundamental biochemicals in aqueous solutions containing sugars, imino acids, urea, amino acid salts, inorganic salts, and sugar salts.

In this work, several new groups have been introduced to represent the activity coefficients for many biochemicals with better accuracy. For sugars, a portion containing asymmetric carbon atoms in an aldohexose molecule was defined as a new group for many stereoisomers. In the case of electrolytes like amino acid salts, the Pitzer-Debye-Hückel term was added to the UNIFAC equation to take the long-range electrostatic interaction into account.

All new interaction parameters for the fundamental biochemicals have been determined from osmotic coefficient as well as activity coefficient data reported in the literature. The new parameters provided good calculated results for these biochemicals.

In addition, the activity coefficient data for the ternary systems water/amino acid/urea and water/amino acid/sucrose were used to determine the interaction parameters between the constituent groups of an amino acid and those of the second solute, urea or sucrose. The correlated results for the system containing urea were in satisfactory agreement with the literature data.     

Correlations for the solubility of normal alkanoic acids ando-toluic acid in binary solvent mixtures

Reasonable estimates of ternary solid-liquid equilibrium can be obtained by application of the Wilson and UNIFAC models. The solubilities of octadecanoic, eicosanoic, docosanoic, and o-toluic acids in binary solvents consisting of a common component (cyclohexane) and a varying second component (heptane, ethanol, methanol, 2-propanol, and 1-butanol) have been measured by a dynamic method from 290 to 340 K. The systems containing cyclohexane-alcohols mixed solvents were found to exhibit a synergistic effect of solubility. The best prediction was obtained for the Wilson equation utilizing temperature dependent _ij parameters. For solubilities in nonpolar solvents, the standard deviations for predicted solubilities are comparable to the experimental errors.Presentation to First International Symposium on Solubility Phenomena, University of Western Ontario, London, Ontario, August 21–23, 1984.     

The solubility and solvation of salts in mixed nonaqueous solvents. 1. Potassium halides in mixed aprotic solvents

The solubilities of potassium fluoride, chloride, and bromide in acetonitrile, N,N-dimethylformamide, and dimethylsulfoxide and in binary mixtures of these solvents were determined at 25°C. The standard molar Gibbs free energies of solution, _solnG°, in the neat solvents were related to the polarizabilities and basicities of the anions and the dipole moments and acidities of the solvents. The values of _solnG° in the mixtures were fitted by expressions from the quasi-lattice quasi-chemical theory. The mean number of each kind of solvent in the nearest environment of the ions was obtained from these results.     

Comparison of permeation resistance of protective gloves to organic solvents with ISO, ASTM and EN standard methods

In this study, the permeation resistance of nitrile and neoprene gloves to benzene and 1,2-dichloroethane was investigated using two permeation cells according to the ISO 6529, ASTM F739, and EN 374-3 standard test methods. The permeability coefficients were found to significantly increase with the flow rate of the collection medium. The appropriate flow rate of nitrogen collection should be higher than 75 and 150 mL/min for the ISO 6529 and ASTM F739 cells, respectively. For an open-loop system, the permeability coefficient of the ISO 6529 cell was obviously greater than that of the ASTM F739 cell, and the difference between these two cells was statistically significant. On the other hand, the breakthrough time was about 20–30 min for either the ISO 6529 or ASTM F739 cell at different flow rates of nitrogen collection. Fick's diffusion coefficient and solubility of permeant in the polymer glove can be specified as alternative test results for standard methods.     

Method for the determination of the solubility of gases in liquids

A rapid and experimentally simple method for the determination of the solubilities of oxygen or hydrogen in liquids is presented The method employs a membrane-enclosed amperometric detector of the well known Clark type to measure the partial pressure of the gas when distributed at equilibrium between the liquid and a gas space for a series of internal volumes of the system. The amounts of all substances and the temperature are maintained constant throughout the series although the internal pressure changes as a result of the volume changes. The glass apparatus is water jacketed for temperature control, has inlet and outlet ports for gas, and the amperometric sensor is mounted in a gas-tight sliding fitting for effecting the volume changes. The liquid content is vigorously stirred by a magnetic bar during measurements. Equations for the interpretation of results at different internal volumes take into account the conservation of the solvent and of the gas, the dependence of the volume of the liquid on the concentration of dissolved gas and Henry's law describing the distribution of the gas between gas and liquid phases at equilibrium. The solution of these equations yields an equation for the dependence of the measured partial pressure on volume, which includes the Henry's law constant H as a parameter. Conditions can usually be arranged to give a straight line dependence of volume on the reciprocal of partial pressure. The method has been applied to several common liquids, and has been shown to produce results which agree with literature solubilities to within about ±5%. Examples which have been studied include oxygen in water (H=4.039 × 10⁶ kPa at 20°C), in acetone (1.25 × 10⁵ kPa at 20°C), in ethanol (1.758 × 10⁵ kPa at 20°C) and in toluene (1.05 × 10⁵ kPa at 20°C) as well as hydrogen in water (6.89 × 10⁶ kPa at 20°C).     

Theoretical and experimental study on Chloroquine drug solubility in supercritical carbon dioxide via the thermodynamic,multi-layer perceptron neural network (MLPNN), and molecular modeling

The design and development of supercritical carbon dioxide (sc-CO₂) based processes for production of pharmaceutical micro/nanoparticles is one of the interesting research topics of pharmaceutical industries owing to its attractive advantages. The solubility of drugs in sc-CO₂ at different temperatures and pressures is an essential parameter which should be determined for this purpose. Chloroquine as a traditional antirheumatic and antimalarial agent is approved as an effective drug for the treatment of Covid-19. Pishnamazi et al. (2021) measured the solubility of this drug in sc-CO₂ at the pressure range of 120–400 bar and temperature range of 308–338 K, and correlated the obtained data using some empirical models. In this work, a comprehensive computational approach was developed to more accurately study the supercritical solubility of Chloroquine. The thermodynamic models include two equations-of-state based models (Peng-Robinson and Soave-Redlich-Kowang) and two activity coefficient-based models (modified Wilson's and UNIQUAC)), as well as, a multi-layer perceptron neural network (MLPNN)) were used for this purpose. Also, molecular modeling was performed to study the electronic structure of Chloroquine and identify the potential centers of intermolecular interactions during the dissolution process. According to the obtained results, all of the theoretical models can predict Chloroquine solubility in sc-CO₂ with acceptable accuracy. Among these models, the MLPNN model possesses the highest precision with the lowest average absolute relative deviation (AARD%) of 1.76 % and the highest R_adj value of 0.999.