Phase equilibria of liquid (water + butyric acid + oleyl alcohol) ternary system

(Liquid + liquid) equilibrium (LLE) data for the ternary system of (water + butyric acid + oleyl alcohol) at T = (298.15, 308.15, and 318.15) K are reported. Complete phase diagrams were obtained by determining solubility and the tie-line data. The reliability of the experimental tie lines was confirmed by using Othmer-Tobias correlation. The UNIFAC method was used to predict the phase equilibrium data. The phase diagrams for the ternary mixtures including both the experimental and correlated tie lines are presented. Distribution coefficients and separation factors were evaluated for the immiscibility region. A comparison of the solvent extracting capability was made with respect to distribution coefficients, separation factors, and solvent-free selectivity bases for T = (298.15, 308.15, and 318.15) K. It is concluded that oleyl alcohol may serve as an adequate solvent to extract butyric acid from its dilute aqueous solutions.     

Liquid-liquid equilibria of water + 3-hydroxy-2-butanone + ethyl ethanoate

(Liquid-liquid) equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 3-hydroxy-2-butanone + ethyl ethanoate) at 298.15 K, 308.15 K and 318.15 K and 101.3 kPa. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using Othmer-Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC method.     

Enthalpies of dilution of l-cystine in aqueous solutions of sodium hydroxide, potassium hydroxide and hydrochloric acid

The enthalpies of dilution of l-cystine in solutions of two strong alkalis and one strong acid have been determined by isothermal flow-mix calorimetry at the temperatures 298.15 K, 303.15 K, 308.15 K, 313.15 K and 318.15 K. Equations of apparent enthalpies of dilution have been obtained from the experimental data in terms of the improved McMillan-Mayer theory. Enthalpic interaction coefficients, h₂, h₃, and h₄, are obtained and the values of pair-wise enthalpic interaction coefficient, h₂, discussed in the light of solute-solute and solute-solvent interactions.     

Ternary liquid–liquid equilibria for (water + terpene + 1-propanol or 1-butanol) systems at the temperature 298.15 K

Liquid–liquid equilibria and tie-lines for the ternary (water + 1-propanol + α-pinene, β-pinene or limonene) and (water + 1-butanol + α-pinene, β-pinene or limonene) mixtures have been measured at T = 298.15 K. The experimental ternary liquid–liquid equilibrium data have been successfully represented using the additional ternary parameters as well as the binary parameters in terms of the extended and modified UNIQUAC models.     

Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hückel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.     

Vapour pressure and excess Gibbs energy of binary 1,2-dichloroethane + cyclohexanone,chloroform + cyclopentanone and chloroform + cyclohexanone mixtures at temperatures from 298.15 to 318.15 K

The vapour pressures of the binary systems 1,2-dichloroethane + cyclohexanone, chloroform + cyclopentanone and chloroform + cyclohexanone mixtures were measured at temperatures between 298.15 and 318.15 K. The vapour pressures vs. liquid phase composition data for three isotherms have been used to calculate the activity coefficients of the two components and the excess molar Gibbs energies, G^E, for these mixtures, using Barker's method. Redlich–Kister, Wilson, NRTL and UNIQUAC equations, taking into account the vapour phase imperfection in terms of the 2-nd virial coefficient, have represented the G^E values. No significant difference between G^E values obtained with these equations has been observed. Our data on vapour–liquid equilibria (VLE) and excess properties of the studied systems are examined in terms of the DISQUAC and modified UNIFAC (Dortmund) predictive group contributions models.     

Excess and deviation properties for the binary mixtures of methylcyclohexane with benzene, toluene, p-xylene, mesitylene, and anisole at T = (298.15, 303.15, and 308.15) K

Experimental data on density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, while speed of sound values at T = 298.15 K are presented for the binary mixtures of (methylcyclohexane + benzene), methylbenzene (toluene), 1,4-dimethylbenzene (p-xylene), 1,3,5-trimethylbenzene (mesitylene), and methoxybenzene (anisole). From these data of density, viscosity, and refractive index, the excess molar volume, the deviations in viscosity, molar refraction, speed of sound, and isentropic compressibility have been calculated. The computed values have been fitted to Redlich-Kister polynomial equation to derive the coefficients and estimate the standard errors. Variations in the calculated excess quantities for these mixtures have been studied in terms of molecular interactions between the component liquids and the effects of methyl and methoxy group substitution on benzene ring.     

Thermodynamic interactions in binary mixtures of anisole with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, and 3-methylbutan-1-ol at T = (298.15, 303.15, and 308.15) K

In this paper, excess thermodynamic functions have been computed from the measured values of density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, ultrasonic velocity at T = 298.15 K over the entire mixture composition range of (anisole with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, or 3-methyl butan-1-ol). Excess molar volume, V^E has been calculated from densities, whereas deviations in viscosity, Δη, were computed from the measured viscosities. From ultrasonic velocities, isentropic compressibilities were calculated, from which deviations in isentropic compressibility, Δk_s have been computed. Lorenz-Lorentz mixture rule was used to compute molar refractivity, R from refractivity index data and from these data, deviations in molar refractivity, ΔR have been computed. Computed thermodynamic quantities have been fitted to Redlich and Kister polynomial equation to derive the coefficients and standard errors between experimental and predicted quantities. Intermolecular interactions between anisole and alkanols have been studied based on the computed excess thermodynamic quantities.     

(Liquid + liquid) equilibria of (tert -amyl ethyl ether + ethanol + water) at several temperatures

(Liquid  +  liquid) equilibrium data of (tert amyl ethyl ether  +  ethanol  +  water) were determined experimentally atT =  (298.15, 308.15, and 318.15) K. The experimental results were correlated with the NRTL and UNIQUAC equations. The correlations were made at each temperature and for the three temperatures simultaneously. The best results were achieved with the NRTL equation, using α =  0.2 for the individual correlations at each temperature and α =  0.1 for the overall correlation. The experimental data were also compared with predicted values by the UNIFAC method.     

Liquid–Liquid Equilibria of Linalool + Ethanol + Water, Water + Ethanol + Limonene, and Limonene + Linalool + Water Systems

The present work was undertaken to determine liquid–liquid equilibria for ternary systems involved in the citrus essential oil terpeneless using dilute alcohol. Tie-line data have been determined for the linalool + ethanol + water, water + ethanol + limonene, and limonene + linalool + water ternary systems at 298.15 K. The experimental data were satisfactorily correlated using the UNIQUAC and NRTL equations, and the obtained binary interaction parameters are reported. The UNIFAC group-contribution method did not allow adequate predictions of liquid–liquid equilibria involved in this study.     

Study of [EMim][ESO4] ionic liquid as solvent in the liquid-liquid extraction of xylenes from their mixtures with hexane

The aim of this work is to determine if the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate is a good solvent for the separation of xylenes and hexane by liquid extraction. With this purpose, liquid-liquid equilibrium (LLE) data for the ternary systems {hexane + o-xylene, or m-xylene, or p-xylene + 1-ethyl-3-methylimidazolium ethylsulfate} were determined at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio, derived from the experimental equilibrium data, were calculated and used to determine if this ionic liquid can be used as a potential solvent for the extraction of xylenes from their mixtures with hexane. The experimental LLE data for the ternary systems were correlated using the NRTL and UNIQUAC models.     

Phase equilibrium and thermophysical properties of mixtures containing a cyclic ether and 1-chloropropane

The phase equilibrium, at T = 298.15 and 313.15 K and several thermophysical properties (density, sound velocity, refractive index) at T = 283.15, 298.15 and 313.5 K of mixtures formed by a cyclic ether (tetrahydropyran, tetrahydrofuran) and 1-chloropropane has been studied. Excess Gibbs functions, excess volumes, excess isentropic compressibilities and refractive index deviations have been obtained from the experimental data. Both the molecular characteristics of the pure compounds and the molecular interactions in the mixing process have been used to analyse the results.     

Liquid–liquid equilibria for butyl tert-butyl ether + (methanol or ethanol) + water at several temperatures

Liquid–liquid equilibrium (LLE) data for butyl tert-butyl ether + (methanol or ethanol) + water were measured experimentally at 298.15, 308.15 and 318.15 K. The experimental data were correlated with the NRTL and UNIQUAC equations. The equations were used to perform the correlation of each temperature data set and for the three temperatures data set simultaneously. The best results were found with UNIQUAC and NRTL (α = 0.1), respectively. Data prediction was carried out using the UNIFAC method, however the results found were not quantitative.     

Thermophysical properties of pure 1-ethyl-3-methylimidazolium methylsulphate and its binary mixtures with alcohols

The density and surface tension of 1-ethyl-3-methylimidazolium methylsulphate, [EMIM][CH₃SO₄] ionic liquid have been measured from (283.15 to 333.15) K. The coefficient of thermal expansion was calculated from the experimental density results using an empirical correlation for T = (283.15-338.15) K. Molecular volume and standard entropies of [EMIM][CH₃SO₄] ionic liquid were obtained from the experimental density values. The surface properties, critical temperature and enthalpy of vaporization were also discussed. Density and surface tension have been measured over the whole composition range for [EMIM][CH₃SO₄] with alcohols (methanol, ethanol, 1-butanol) binary systems at 298.15 K and atmospheric pressure. Excess molar volumes and surface tension deviations for the binary systems have been calculated and were fitted to a Redlich-Kister equation to determine the fitting parameters and the root mean square deviations.     

Aqueous biphasic systems composed of ionic liquid and fructose

Liquid–liquid equilibria data of the [Bmim]BF₄ + fructose + water system were determined at 298.15, 308.15, 31815 K. It was found that the liquid–liquid equilibria can be formed over a wide component range and the effect of the temperature on the phase equilibria is obvious within the fructose concentration changing from 3 to 40%. The binodal curves were correlated using a five-parameter equation, and the tie lines were fitted the Othmer–Tobias and Bancroft correlations. Correlation coefficients for the equations exceeded 0.99.     

Measurement and correlation of phase equilibria in aqueous two-phase systems containing polyvinylpyrrolidone and di-potassium tartrate or di-potassium oxalate at different temperatures

Experimental (liquid + liquid) equilibrium (LLE) measurements and the phase diagram have been determined for aqueous two-phase systems containing polyvinylpyrrolidone (PVP) and di-potassium oxalate or di-potassium tartrate at T = (298.15, 308.15, and 318.15) K. Also, the effects of temperature on the binodal curve and tie-lines have been studied. The Merchuk equation was used to correlate the binodal curves of these systems. Furthermore, several suitable equations were used to fit the tie-line data points. The results show that at each temperature, the agreement between the correlated and the experimental values is good with all of these equations. Also, the effects of the type of salt on LLE are discussed.     

Isothermal (vapour + liquid) equilibria and excess Gibbs free energies in some binary (cyclopentanone + chloroalkane) mixtures at temperatures from 298.15 K to 318.15 K

The vapour pressures of binary (cyclopentanone + 1-chlorobutane, +1,3-dichloropropane, and +1,4-dichlorobutane) mixtures, were measured at the temperatures of (298.15, 308.15, and 318.15) K. The vapour pressures vs. liquid phase composition data have been used to calculate the excess molar Gibbs free energies G^E of the investigated systems, using Barker’s method. Redlich–Kister, Wilson and NRTL equations, taking into account the vapor phase imperfection in terms of the second virial coefficient, have represented the G^E values. No significant difference between G^E values obtained with these equations has been observed.     

On the density and viscosity of (water + dimethylsulphoxide) binary mixtures

Density and viscosity of (water + dimethylsulphoxide) were measured precisely over the whole composition range at T = (298.15, 303.15, 308.15, 313.15, and 318.15) K. Differences between values from different authors are clarified and more reliable partial molar volumes are obtained.     

Measurement and correlation of liquid–liquid equilibria for ternary systems {cyclooctane + aromatic hydrocarbon + 1-ethyl-3-methylpyridinium ethylsulfate} at T = 298.15 K and atmospheric pressure

This work reports liquid–liquid equilibrium (LLE) results for the ternary systems {cyclooctane + benzene + 1-ethyl-3-methylpyridinium ethylsulfate}, {cyclooctane + toluene + 1-ethyl-3-methylpyridinium ethylsulfate}, and {cyclooctane + ethylbenzene + 1-ethyl-3-methylpyridinium ethylsulfate} at T = 298.15 K and under atmospheric pressure. The selectivity, percent removal of aromatic, and distribution coefficient ratio, derived from the tie-line data, were calculated to determine if this ionic liquid is a good solvent for the extraction of aromatics from cyclooctane. The phase diagrams for the ternary systems are shown, and the tie-lines correlated with the NRTL model have been compared with the experimental data. The consistency of the experimental LLE data was ascertained using the Othmer–Tobias and Hand equations. No data for mixtures presented here have been found in the literature.     

Partial molar volume of paracetamol in water, 0.1 M HCl and 0.154 M NaCl at T = (298.15, 303.15, 308.15 and 310.65) K and at 101.325 kPa

The apparent molar volume of paracetamol (4-acetamidophenol) in water, 0.1 M HCl and 0.154 M NaCl as solvents at (298.15, 303.15, 308.15 and 310.65) K temperatures and at a pressure of 101.325 kPa were determined from the density data obtained with the help of a vibrating-tube Anton Paar DMA-48 densimeter. The partial molar volume, V_m, of paracetamol in these solvents at different temperatures was evaluated by extrapolating the apparent molar volume versus molality plots to m = 0. In addition, the partial molar expansivity, E^°, the isobaric coefficient of thermal expansion, α_p, and the interaction coefficient, S_v, have also been computed. The expansivity data show dependence of E^° values on the structure of the solute molecules.