Determination and correlation of the solubility for diosgenin in alcohol solvents

Using a laser monitoring technique, the solubility of diosgenin in ethanol, 1-propanol, 1-butanol, isobutyl alcohol, tert-butanol, 1-pentanol, and iso-octyl alcohol was measured over the temperature range from (290.15 to 330.15) K at atmospheric pressure. Its corresponding (solid + liquid) equilibrium data will provide essential support for industrial design and further theoretical studies. From the experimental results, the solubility of diosgenin in ethanol, 1-propanol, 1-butanol, isobutyl alcohol, tert-butanol, 1-pentanol, and iso-octyl alcohol was found to increase with increasing temperature and decrease with the increase of the polarity of the alcohols solvents. The Apelblat equation, the ideal model and the λh equation were used to correlate the solubility values. The results showed that the three models mentioned above agreed well with the experimental data.     

Ternary equilibrium data of mixtures consisting of 2-butanol,water, and heavy alcohols at T = 298.2 K

Experimental solubility curves and tie-line data for the (water + 2-butanol + organic solvents) systems were obtained at T = 298.2 K and atmospheric pressure. The organic solvents were four heavy alcohols, i.e. 1-hexanol, 1-heptanol, 1-octanol, and 1-decanol. The consistency of the experimental tie-line data was determined through the Othmer–Tobias and Bachman equations. Distribution coefficients and separation factors were calculated to evaluate the extracting capability of the solvents. The experimental data were correlated using the NRTL (α = 0.2) and UNIQUAC models, and binary interaction parameters were obtained. The average root mean square deviation values between the experimental and calculated data show the capability of these models, in particular NRTL model, in correlation of the phase behavior of the ternary systems.     

Solubility measurement and modelling of 1,8-dinitronaphthalene in nine organic solvents from T = (273.15 to 308.15) K and mixing properties of solutions

The solubility of 1,8-dinitronaphthalene in acetonitrile, methanol, ethanol, trichloromethane, isopropanol, acetone, toluene, ethyl acetate and butyl alcohol were obtained experimentally at temperatures ranging from (273.15 to 308.15) K under 0.1 MPa by using a gravimetric method. The solubility of 1,8-dinitronaphthalene in those solvents increases with an increase in temperature. The solubility values decrease according to the following order: acetone > (acetonitrile, ethyl acetate) > trichloromethane > toluene > methanol > ethanol > isopropanol > butyl alcohol. Three models, the modified Apelblat equation, Wilson and NRTL were used to correlate the solubility of 1,8-dinitronaphthalene in the solvents studied. The calculated solubility by the modified Apelblat equation provides better agreement than those evaluated by the other two models. The regressed results via the three models are all acceptable for the solubility of 1,8-dinitronaphthalene in the selected solvents. Furthermore, the mixing Gibbs energy, mixing enthalpy, and mixing entropy for per 1 mol of mixture of 1,8-dinitronaphthalene and solvents were calculated based on the Wilson model. The dissolution process of 1,8-dinitronaphthalene in the selected solvents is spontaneous and exothermic.     

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.     

Determination and correlation of solubility of tylosin tartrate in alcohol mixtures

Data on (solid + liquid) equilibrium of tylosin tartrate in {methanol + (ethanol, 1-propanol or 2-propanol)} solvents will provide essential support for industrial design and further theoretical studies. In this study, the solubility of tylosin tartrate in alcohol mixtures was measured over temperature range from (278.15 to 323.15) K under atmospheric pressure by a gravimetric method. From the experimental results, the solubility of tylosin tartrate in selected solvents noted above was found to increase with increasing temperature and mass fraction of methanol. The solubility data were correlated with the modified Apelblat equation, the λh equation and van’t Hoff equation. The results showed that the three equations agreed well with the experimental values, and that the modified Apelblat equation was more accurate than the λh equation and van’t Hoff equation. Further, the standard enthalpy, standard entropy and standard Gibbs free energy of solution of tylosin tartrate in mixed solvents were calculated according to solubility results, model parameters with modified Apelblat equation and van’t Hoff equation.     

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.     

Thermodynamic properties of CO2 absorption in hydroxyl ammonium ionic liquids at pressures of (100–1600) kPa

Solubility of CO₂ in six hydroxyl ammonium ionic liquids 2-hydroxyethanaminium acetate [hea], bis(2-hydroxyethyl)ammonium acetate [bheaa], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium acetate [hhemea], 2-hydroxyethanaminium lactate [hel], bis(2-hydroxyethyl)ammonium lactate [bheal], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium lactate [hhemel] at temperatures (298.15, 313.15, and 328.16) K and pressures ranging from (100 to 1600) kPa was determined. From the experimental solubility data, the Henry’s constant of CO₂ for each hydroxyl ammonium ionic liquids was estimated and reported as a function of temperature. Furthermore, enthalpy and entropy of absorption were obtained from estimated Henry’s constant. The results showed that the solubility increase with increasing pressure and decrease with increasing temperature and the solubility of CO₂ in these six hydroxyl ammonium ionic liquids was in sequence: [hea] > [bheaa] > [hel] > [bheal] > [hhemel] > [hhemea].     

Measurement and correlation of solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in seven solvents at different temperatures

The solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in water, methanol, ethanol, 1-propanol, 1-butanol, acetone, and ethyl acetate from T = (288.2 to 328.2) K were measured. The solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in selected solvents increase with increasing temperature, respectively. The experimental solubility data were correlated by a simplified thermodynamic equation and a three-parameter empirical equation.     

(Liquid + liquid) equilibria in the binary systems (aliphatic,or aromatic hydrocarbons + 1-ethyl-3-methylimidazolium ethylsulfate,or 1-butyl-3-methylimidazolium methylsulfate ionic liquids)

(Liquid + liquid) equilibria of 14 binary systems composed of n-hexane, n-heptane, benzene, toluene, o-xylene, m-xylene, or p-xylene and 1-ethyl-3-methylimidazolium ethylsulfate, [emim]EtSO₄, or 1-butyl-3-methylimidazolium methylsulfate, [bmim]MeSO₄, ionic liquids have been done in the temperature range from (293.2 to 333.2) K. The solubility of aliphatic is less than those of the aromatic hydrocarbons. In particular, the solubility of hydrocarbons in both ionic liquids increases with the temperature in the order n-heptane < n-hexane < m-xylene < p-xylene < o-xylene < toluene < benzene. Considering the high solubility of aromatics and the low solubility of aliphatic hydrocarbons as well as totally immiscibility of the ionic liquids in all hydrocarbons, these new green solvents may be used as potentials extracting solvents for the separation of aromatic and aliphatic hydrocarbons.     

Excess molar volumes and viscosities of (1,1,2,2-tetrabromoethane + 1-alkanols) at T = (293.15 and 303.15) K

Density and viscosity measurements for binary mixtures of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-hexanol, or + 1-heptanol, or + 1-octanol, or + 1-decanol) at T = (293.15 and 303.15) K, have been conducted at atmospheric pressure. The excess molar volumes V^E, have been calculated from the experimental measurements, and the results were fitted to Redlich–Kister equation. The viscosity data were correlated with the model of Grunberg and Nissan, and McAllister four-body model. The excess molar volumes of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-haxanol, or + 1-heptanol, or + 1-octanol) had a sigmoidal shape and the values varied from negative to positive with the increase in the molar fraction of 1,1,2,2-tetrabromoethane. The remaining binary mixture of (1,1,2,2-tetrabromoethane + 1-decanol) was positive over the entire composition range. The effects of the 1-alkanol chain length as well as the temperature on the excess molar volume have been studied. The results have been qualitatively used to explain the molecular interaction between the components of these mixtures.     

Solubilities of oleanolic acid and ursolic acid in (ethanol + water) mixed solvents from T = (292.2 to 328.2) K

The solubility of oleanolic acid and of ursolic acid in (ethanol + water) mixed solvents was measured over the temperature range of (292.2 to 328.2) K. The solubility of oleanolic acid and of ursolic acid in the (ethanol + water) mixed solvent systems increase with increasing the mole fraction of ethanol in mixed solvents. The experimental solubility data are correlated by a simplified thermodynamic equation and the modified Apelblat equation.     

Measurement and correlation of solubility of dodecanedioic acid in different pure solvents from T = (288.15 to 323.15) K

The solubility of dodecanedioic acid in ethanol, acetic acid, acetone, butanone, 3-pentanone and ethyl acetate has been measured at temperatures ranging from (288.15 to 323.15) K by a static analytic method at atmospheric pressure. At a given temperature, the order of solubility is ethanol > acetic acid > acetone > butanone > 3-pentanone > ethyl acetate. Molecular modeling study using Materials Studio DMol³ (Accelrys Software Inc.) indicated that the solubility of dodecanedioic acid depends not only on the polarities of the solvents but also on the interactions between dodecanedioic acid and solvent molecules. Furthermore, the modified Apelblat equation was used to represent the temperature dependence of the mole fraction solubility. Finally, the molar Gibbs energy, enthalpy, and entropy of the solution were calculated using the fitting parameters of the modified Apelblat equation.     

Experimental measurement and modelling of KBr solubility in water,methanol, ethanol,and its binary mixed solvents at different temperatures

A simple and accurate apparatus has been designed to measure the solubilities of potassium bromide by an analytical method. Salt solubility data have been measured in water, methanol, ethanol, (water  +  methanol), (water  +  ethanol), and (methanol  +  ethanol) solvents in the temperature range between 298.15 K and 353.15 K.A new formulation is presented for the calculation of salt solubility in pure and mixed solvents as a function of the temperature and solvent composition. This formulation is based on the symmetric convention for the normalization of the activity coefficients for all species in solution, and makes possible direct access to the solubility product of the salt in terms of its thermodynamic properties. The new solubility data measured in this work, as well as experimental information from the open literature, are used to estimate the interaction parameters of the two models proposed here. One model combines the original Universal Quasi Chemical (UNIQUAC) equation with a Pitzer–Debye–Hückel expression to take into account the long-range interaction forces; the other model only considers the short-range forces through the UNIQUAC equation with linear temperature dependent salt/solvent interaction parameters. Both models correlate satisfactorily the solubility data, although temperature and electrostatic effects are both very important in this type of equilibrium. Finally, some conclusions are drawn concerning the models versatility to represent other type of equilibrium data and prediction capabilities.     

Experimental measurement and modelling of solubility of inosine-5′-monophosphate disodium in pure and mixed solvents

The solubility of biological chemicals in solvents provide important fundamental data and is generally considered as an essential factor in the design of crystallization processes. The equilibrium solubility data of inosine-5′-monophosphate disodium (5′-IMPNa₂) in water, methanol, ethanol, acetone, as well as in the solvent mixtures (methanol + water, ethanol + water, acetone + water), were measured by an isothermal method at temperatures ranging from (293.15 to 313.15) K. The measured data in pure and mixed solvents were then modelled using the modified Apelblat equation, van’t Hoff equation, λh equation, ideal model and the Wilson model. The modified Apelblat equation showed the best modelling results, and it was therefore used to predict the mixing Gibbs free energies, enthalpies, and entropies of 5′-IMPNa₂in pure and binary solvents. The positive values of the calculated partial molar Gibbs free energies indicated the variations in the solubility trends of 5′-IMPNa₂. Water and ethanol (in the binary mixture with water) were found to be the most effective solvent and anti-solvent, respectively.     

(Solid + liquid) equilibria of (nalkanes + ethyl 1,1-dimethylpropyl ether)

(Solid  +  liquid) equilibria (s.l.e.) have been measured atT >  280 K for (octadecane, or nonadecane, or eicosane, or heneicosane, or docosane, or tricosane, or tetracosane, or hexacosane, or heptacosane, or octacosane  +  ethyl 1,1-dimethylpropyl ether ETAE). The experimental results are compared with values calculated by means of the Wilson, UNIQUAC and NRTL equations utilizing parameters derived from the experimental s.l.e. The existence of a (solid  +  solid) first-order phase transition in hydrocarbons has been taken into consideration in the solubility calculations. The solubility of hydrocarbons in branched-chain ethers is lower than that in n -alkanes but higher than that in cycloalkanes, branched alkanes, 1-alcohols andtert -alcohols. The best correlation of the solubility data has been obtained by the NRTL equation where the average root-mean-square deviation of the solubility temperatures is 0.36 K.     

Thermodynamics of transfer of naphthalene and 2-naphthoic acid from water to (water + ethanol) mixtures at T=298.15 K

Standard thermodynamic functions of transfer of naphthalene and 2-naphthoic acid from water to (water + ethanol) mixtures at T=298.15 K have been determined from solubility measurements at different temperatures. Standard free energies of transfer of both naphthalene and 2-naphthoic acid showed decreasing tendency with the increasing x(EtOH), and the standard entropy and enthalpy of transfer exhibited a change of double peaks with x(EtOH). The Δ_trG⁰ of 2-naphthoic acid decreased more rapidly than that of naphthalene when x(EtOH) < 0.746 and lower than that of naphthalene when x(EtOH) >0.746 at T=298.15 K. The double peaks in the curves of standard entropy and enthalpy of transfer illustrated that the microstructure of the series of mixed solvents of (water + ethanol) underwent a variable process from ordered to disordered and then from disordered to ordered. The results mean that there is a relatively ordered structure near x(EtOH)=0.13 in the (water + ethanol) solutions besides the existence of a clathrate structure in the water-rich region.     

Solubility of H2S in ionic liquids [hmim][PF6], [hmim][BF4], and [hmim][Tf2N]

The solubility of hydrogen sulphide in three ionic liquids, viz. 1-hexyl-3-methylilmidazolium hexafluorophosphate ([hmim][PF₆]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF₄]), and 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([hmim][Tf₂N]), at temperatures ranging from 303.15 K to 343.15 K and pressures up to 1.1 MPa were determined. The solubility values were correlated using the Krichevsky–Kasarnovsky equation and Henry’s constants were obtained at different temperatures. Partial molar thermodynamic functions of solvation such as standard Gibbs free energy, enthalpy, and entropy were calculated from the solubility results. Comparison of the values obtained show that the solubility of H₂S in these three ionic liquids was in the sequence: [hmim][BF₄] > [hmim][PF₆] ≈ [hmim][Tf₂N].     

Measurement and correlation of solubility of 4-chloro-2,5-dimethoxynitrobenzene and 4-chloro-2,5-dimethoxyaniline in methanol,ethanol, xylene and toluene

The solubility of 4-chloro-2,5-dimethoxynitrobenzene (CDMB) and 4-chloro-2,5-dimethoxyaniline (CDMA) in methanol, ethanol, xylene and toluene was measured over the temperatures range from (278 to 338) K by the dynamic method using a laser monitoring observation technique. The solubility in all solvents increased with temperature and the greatest solubility of both systems was obtained in toluene. The Wilson and the NRTL models were applied to correlate the experimental results. The root-mean-square deviations for the system of (CDMB + solvent) ranged from T = (0.11 to 0.34) K and (0.08 to 0.33) K calculated by the Wilson and the NRTL models, respectively, while for the system of (CDMA + solvent) the root-mean-square deviations ranged from T = (0.11 to 0.32) K and (0.14 to 0.33) K. The melting points and enthalpies of fusion of CDMA and CDMB were determined by differential scanning calorimetry (DSC). Toluene was found to be the preferred solvent for the reduction of CDMB to CDMA from the point of view of reaction and product separation     

Solubility of CO2 in 1-(2-hydroxyethyl)-3-methylimidazolium ionic liquids with different anions

The solubility of carbon dioxide in a series of 1-(2-hydroxyethyl)-3-methylimidazolium ([hemim]⁺) based ionic liquids (ILs) with different anions, viz. hexafluorophosphate ([PF₆]^?), trifluoromethanesulfonate ([OTf]^?), and bis-(trifluoromethyl)sulfonylimide ([Tf₂N]^?) at temperatures ranging from 303.15 K to 353.15 K and pressures up to 1.3 MPa were determined. The solubility data were correlated using the Krichevsky–Kasarnovsky equation and Henry’s law constants were obtained at different temperatures. Using the solubility data, the partial molar thermodynamic functions of solution such as Gibbs free energy, enthalpy, and entropy were calculated. Comparison showed that the solubility of CO₂ in the ILs studied follows the same behaviour as the corresponding conventional 1-ethyl-3-methylimidazolium ([emim]⁺) based ILs with the same anions, i.e. [hemim][NTf₂] > [hemim][OTf] > [hemim][PF₆] > [hemim][BF₄].     

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.