Solubility of hydrogen sulfide in organic solvents

The solubilities of hydrogen sulfide expressed in mole fractions may be related, through multiparameter equations, to parameters that account for the specific and nonspecific solvation ability of the solvent and for the cohesion energy. The key factors are the self-association of the solvent, which reduces the solubility, and the complexing ability with hydrogen sulfide, which increases the solubility.     

Solubility of sulphur dioxide in polar organic solvents

The solubility of sulphur dioxide in N,N-dimethylformamide, dimethyl sulphoxide, N,N-dimethyl acetamide, sulpholane, tributyl phosphate and diethanolamine has been determined. A solubility model is proposed and the solubilities calculated by the model show good agreement with experimental data.     

Solubility of KF in four organic solvents and thermodynamic dissolution functions

The solubilities of potassium fluoride (KF) in protic and aprotic polar solvents (N,N-dimethylethanolamine, diethanolamine, pyridine, and sulfolane) were measured at temperatures ranging from 308.73 to 367.37 K, and the data were correlated using the modified Apelblat equation. The dissolution enthalpy and dissolution entropy were calculated from the solubility data. The interactions between solute and solvent were discussed. The data obtained can be helpful in the search of optimal ways of preparation of 2,3,4,5-tetrafluorobenzoic acid.     

Solubility of naproxen in several organic solvents at different temperatures

By using the van’t Hoff and Gibbs equations the thermodynamic functions Gibbs free energy, enthalpy, and entropy of solution, were evaluated from solubility data of naproxen (NAP) determined at several temperatures in octanol, isopropyl myristate, chloroform, and cyclohexane, as pure solvents. The water-saturated organic solvents also were studied except cyclohexane. The excess free energy and the activity coefficients of the solutes, and the mixing and solvation thermodynamic quantities were also determined. The NAP solubilities were higher in chloroform and octanol with respect to those obtained in cyclohexane. In addition, by using literature values for NAP aqueous solubility, the thermodynamic functions relative to transfer of this drug from water to organic solvents were also estimated.     

Solubility and limiting activity coefficient of simvastatin in different organic solvents

Equilibrium mole fraction solubility of Zocor^® (simvastatin) a pharmaceutically important compound, was measured between 279 and 315 K, in fifteen different industrial-relevant organic solvents including: methyl acetate, ethyl acetate, propyl acetate, iso-propyl acetate, butyl acetate, iso-butyl acetate, sec-butyl acetate, tert-butyl acetate, and ethanol, propanol, 1-butanol, 2-butanol, 1-pentanol, 1-hexanol, and 1-octanol. Fusion enthalpy, Δ_fusH, melting point temperature, T_m, were measured to be 32,169 J/mol, 412.6 K, respectively; and the difference in the molar heat capacity (at constant pressure) of the liquid, and solid form of simvastatin, ΔC_P, was approximated (by extrapolation) to be 230 J/mol K. Dissolution of simvastatin was found to be endothermic, and entropically favorable. The activity coefficient at infinite dilution of simvastatin in each solvent was calculated from the experimental data, then fitted to Gibbs–Helmholtz equation to estimate the limiting partial molar excess enthalpies, , and the limiting partial molar excess entropies, . The data was also fitted to the non-random-two-liquid (NRTL) activity coefficient equation to generate the model interaction parameters for dissolution of simvastatin in the organic solvents studied here.     

Solubility and solution thermodynamics of sorbic acid in eight pure organic solvents

By the gravimetric method, the solubility of sorbic acid in eight solvents including ethanol, 2-propanol, methanol, 1-butanol, ethyl acetate, methyl tert-butyl ether, acetone and acetonitrile was determined over a temperature range from 285.15 to K at atmospheric pressure. For the temperature range investigated, the solubility of sorbic acid in the solvents increased with increasing temperature. The experimental values were correlated with the linear solvation energy relationship, modified Apelblat equation, λh equation, non-random two-liquid (NRTL) model, and Wilson model. On the other hand, the enthalpy, entropy and Gibbs free energy of dissolution were obtained from these solubility values by using the van’t Hoff and Gibbs equations. The excess enthalpy of solution was estimated on the basis of λh equation. Furthermore, the a priori predictive model COSMO-RS was employed to predict the solubility of sorbic acid in selected solvents and reasonable agreement with experimental values is achieved.     

Solubility and aggregation studies of copper(II) dodecanoate in organic solvents

Summary The solubility of copper(II) dodecanoate in tetrachloromethane, heptane, toluene and xylene has been determined as a function of temperature by employing gravimetric and atomic absorption methods. Each system shows an abrupt increase in solubility at a particular temperature and aggregation numbers have been obtained by vapour pressure osmometry to determine whether this is due to the onset of micellisation.     

Solubility of long-chain fatty acid esters in selected organic one- and two-component solvents

Three long-chain ethylene glycol monoesters of stearic, eicosanoic and behenic acids have been synthesized and carefully purified. Their solubilities in 25 pure solvents and in 28 binary solvent systems have been investigated by a synthetic method over a temperature range from 280 to 320 K. The systems containing cyclohexane+alcohols and chlorohydrocarbons+alcohols mixed solvents were found to exhibit a solubility synergistic effect. The results of these measurements were correlated by the Wilson equation utilizing temperature dependent _ij parameters.     

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.     

Solubility of daidzin in different organic solvents and (ethyl alcohol + water) mixed solvents

The solubility of daidzin in different organic solvents and (ethyl alcohol + water) mixed solvents was measured by high performance liquid chromatography (HPLC) analysis method from T = (283.2 to 323.2) K at atmosphere pressure. The results show that at higher temperature more daidzin dissolves, and moreover, the solubility increases with the ethyl alcohol mole fraction increase in the (ethyl alcohol + water) mixed solvents. The experimental solubility values were correlated by a simplified thermodynamic equation, λh equation and modified Apelblat equation. Based on the solubility of daidzin, the enthalpy and entropy of solution were also evaluated by van’t Hoff equation. The results illustrated that the dissolution process of daidzin is endothermic and entropy driven.     

Solubility of diosgenin in different solvents

The solubility of diosgenin in methanol, ethanol (95%), isopropanol, acetone, acetic ether, and propyl acetate were measured at temperatures from (295.15 to 330.15) K using the synthetic method by a laser monitoring observation technique at atmospheric pressure. Its corresponding (solid + liquid) equilibrium data will provide essential support for industrial design and further theoretical studies. The solubility data of diosgenin in isopropanol, acetone, ethanol (95%), and acetic ether were correlated with Apelblat equation, and the experimental data of diosgenin in methanol and propyl acetate were also correlated with the λh model. The calculated values were good in agreement with the experimental values.     

Solubility of ozone in some flourocarbon solvents

The solubilities of ozone 0-6 Wt% in air or oxygen, in 14 Fluorocarbon solvents have been determined at ambient temperature. Solubilities ranged from 50 to 700 ppm (wt) for a gas phase 0₃ concentration of 6 Wt%. Compounds with 0₃ solubilities <130 ppm (wt), exhibited approximate Henry's Law behavior, whereas those compounds with O₃ solubilities >200 ppm (wt) showed apprarent marked Henry's Law deviations.     

Solubility of porphyrin macrocycles in mixed solvents

A method based on the statements of molecular association theory and a simple lattice model (ASL = Associated Solution + Lattice) is used to calculate the solubility of a series of porphyrin macrocycles (blood porphyrins) in binary solvents (tetrachloromethane-ethyl acetate, tetrachloromethane-methanol). Separate contributions to solubility are identified and the relative role of different factors determining the solubility dependence on the mixed solvent composition is analyzed. The calculated solubility values are in good agreement with the experimental data obtained for the studied systems by the isothermal saturation method with a spectrophotometric control of concentrations.     

Regular trends in distribution of substituted benzoic acids between organic solvents and water

The influence of physicochemical properties of organic solvents on the distribution constants of aromatic carboxylic acids between the organic and aqueous phases was examined.     

Lipase catalysis in organic solvents

The conditions for esterification and transesterification catalyzed by porcine pancreatic lipase in organic media were studied. It was found that the enzyme reaction was dependent on the following factors: the pH at which the enzyme powder was prepared from its solution, the polarity of organic media, the reaction temperature, the water content in reaction system, and the substrate structures. Effects of the above factors on enzyme activity were discussed.     

Inorganic polarography in organic solvents

A review of inorganic polarography in organic solvents is presented.     

Asphaltene aggregation in organic solvents

Asphaltenic solids formed in the Rangely field in the course of a carbon dioxide flood and heptane insolubles in the oil from the same field were used in this study. Four different solvents were used to dissolve the asphaltenes. Near-infrared (NIR) spectroscopy was used to determine the onset of asphaltene precipitation by heptane titration. When the onset values were plotted versus asphaltene concentrations, distinct break points (called critical aggregation concentrations (CAC) in this paper) were observed. CACs for the field asphaltenes dissolved in toluene, trichloroethylene, tetrahydrofuran, and pyridine occurred at concentrations of 3.0, 3.7, 5.0, and 8.2 g/l, respectively. CACs are observed at similar concentrations as critical micelle concentrations (CMC) for the asphaltenes in the solvents employed and can be interpreted to be the points at which rates of asphaltene aggregations change. CMC values of asphaltenes determined from surface tension measurements (in pyridine and TCE) were slightly higher than the CAC values measured by NIR onset measurements. The CAC for heptane-insoluble asphaltenes in toluene was 3.1 g/l. Thermal gravimetric analysis (TGA) and elemental compositions of the two asphaltenes showed that the H/C ratio of the heptane-insoluble asphaltenes was higher and molecular weight (measured by vapor pressure osmometry) was lower.     

Ion exchange in organic solvents

Studies on the partitioning of plutonium from 30% TBP by ion-exchange absorption on macroporous cation exchanger Amberlyst-15 have been described. Detailed loading experiments indicate that the resin absorbs plutonium in preference to uranium from loaded organic phase at low organic phase acidities (around 0.2M). Absorption behaviour of some fission products on the resin in 30% TBP is also reported. Possibility of using this procedure as an alternate method for plutonium partitioning from IAP stream of Purex process has been discussed.