Liquid–liquid equilibrium of (water + 1-propanol + 1-pentanol) system at 298.15 and 323.15 K

Liquid–liquid equilibrium data for the ternary system water + 1-propanol + 1-pentanol have been determined experimentally at 298.15 and 323.15 K using “static–analytic” apparatus involving ROLSI™ samplers. The experimental data are correlated considering both NRTL and UNIQUAC activity coefficient models. The results obtained show the ability of both models for the determination of liquid–liquid equilibrium data of the studied system. The reliability of the experimental tie-line data is determined through the Othmer–Tobias and Bachman equations.     

Vapor–liquid equilibrium for the binary systems tetrahydrothiophene + toluene and tetrahydrothiophene + o-xylene at 368.15 K and 383.15 K

Isothermal vapor–liquid equilibrium (VLE) for tetrahydrothiophene + toluene and tetrahydrothiophene + o-xylene at 368.15 K and 383.15 K was measured with a recirculation still. Liquid- and vapor-phase compositions were determined with gas chromatography. All systems exhibit a small positive deviation from Raoult's law and show nearly ideal behavior. All VLE measurements passed the point test used. The experimental results were correlated with the Wilson model and compared with COSMO-SAC predictive models. COSMO-SAC predictions show a slight negative deviation from Raoult's law for all systems measured. Raoult's law can be used to describe all systems studied. The activity coefficients at infinite dilution are presented.     

Isobaric vapor–liquid–liquid equilibrium and vapor–liquid equilibrium for the system water–ethanol-1,4-dimethylbenzene at 101.3 kPa

An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer has been used to determine vapor–liquid (VLE) and vapor–liquid–liquid (VLLE) equilibria. Consistent data have been obtained for the ternary water + ethanol + p-xylene system at 101.3 kPa for temperatures in the range of 351.16–365.40 K. Experimental results have been used to check the accuracy of the UNIFAC, UNIQUAC and NRTL models in the liquid–liquid region of importance in the dehydration of ethanol by azeotropic distillation.     

Isothermal vapor–liquid equilibrium at 333.15 K,excess molar volumes and refractive indices at 298.15 K for mixtures of tert-amyl methyl ether + ethanol + 2,2,4-trimethylpentane

Isothermal vapor–liquid equilibrium data at 333.15 K are measured for the binary system tert-amyl methyl ether + ethanol and tert-amyl methyl ether + 2,2,4-trimethylpentane and for ternary system tert-amyl methyl ether + ethanol + 2,2,4-trimethylpentane by using headspace gas chromatography. The experimental vapor–liquid equilibrium data were correlated with G^E models (Margules, van Laar, Wilson, NRTL, UNIQUAC) equations. The excess volume and deviations in molar refractivity data are also reported for the same binary and ternary systems at 298.15 K. These data were correlated with the Redlich–Kister equation for the binary systems and the Cibulka equation for the ternary system, respectively. The experimental ternary excess volume and deviations in molar refractivity data, were also compared with the estimated values from the binary contribution models of Tsao–Smith, Kohler, Rastogi and Radojkovi?.     

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.     

Solid–liquid phase equilibria in the system K2SO4–MnSO4–H2O at 298 K and 313 K

Phase equilibria studies of the system K₂SO₄–MnSO₄–H₂O published revealed discrepancies between the data presented in the literature regarding the solid phases formed at ambient temperatures. The solubility in the system at 298 K and 313 K was determined. At 298 K, the existence of the double salt K₂SO₄·3MnSO₄·5H₂O and of MnSO₄·H₂O was confirmed. The examinations at 313 K showed the formation of the stable solid phases MnSO₄·H₂O, K₂SO₄·2MnSO₄, K₂SO₄·MnSO₄·1.5H₂O, K₂SO₄ and the formation of a metastable phase K₂SO₄·MnSO₄·2H₂O.     

Liquid–liquid equilibrium data for binary perfluoroalkane (C6 and C8) + n-alkane systems

This study aims to make detailed measurements of the solubility data for perfluoroalkane + n-alkane systems. Using a laser-scattering technique developed in our laboratory, we determined the liquid–liquid equilibria (LLE) for three binary mixtures: perfluorohexane + n-hexane, perfluorohexane + n-octane, and perfluorooctane + n-octane. The experimental LLE data were represented by the NRTL equation. In addition, the activity coefficients obtained from the experimental LLE data were compared with those obtained from the vapor–liquid equilibrium (VLE) data.     

Vapor–liquid equilibrium for binary system of tetrahydrothiophene + 2,2,4-trimethylpentane and tetrahydrothiophene + 2,4,4-trimethyl-1-pentene at 358.15 and 368.15 K

Isothermal vapor–liquid equilibrium (VLE) for tetrahydrothiophene + 2,2,4-trimethylpentane and tetrahydrothiophene + 2,4,4-trimethyl-1-pentene at 358.15 and 368.15 K were measured with a circulation still. All systems studied exhibit positive deviation from Raoult's law. No azeotropic behavior was found in all systems at the measured temperatures. The experimental results were correlated with the Wilson model and compared to COSMO-SAC predictive model. Analyses of liquid and vapor phase composition were determined with gas chromatography. All VLE measurements passed the three thermodynamic consistency tests used. The activity coefficients at infinite dilution are also presented.     

Isothermal vapor–liquid equilibrium at 333.15 K and excess molar volumes and refractive indices at 298.15 K for the mixtures of di-methyl carbonate,ethanol and 2,2,4-trimethylpentane

Isothermal vapor–liquid equilibrium data at 333.15 K are measured for the binary system ethanol + 2,2,4-trimethylpentane and for ternary system di-methyl carbonate (DMC) + ethanol + 2,2,4-trimethylpentane by using headspace gas chromatography. The experimental binary and ternary vapor–liquid equilibrium data were correlated with different activity coefficient models. Excess volume and deviations in molar refractivity data are also reported for the binary systems DMC + ethanol and DMC + 2,2,4-trimethylpentane and the ternary system DMC + ethanol + 2,2,4-trimethylpentane at 298.15 K. These data were correlated with the Redlich-Kister equation for the binary systems and the Cibulka equation for the ternary system, respectively. The ternary excess volume and deviations in molar refractivity data were also compared with estimated values from the binary contribution models of Tsao–Smith, Kohler, Rastogi and Radojkovi?.     

Measurement and calculation of vapor–liquid equilibria for methanol + glycerol and ethanol + glycerol systems at 493–573 K

The vapor–liquid equilibria for methanol + glycerol and ethanol + glycerol systems were measured by a flow method at 493–573 K. The pressure conditions focused in this work were 3.03–11.02 MPa for methanol + glycerol system and 2.27–8.78 MPa for ethanol + glycerol system. The mole fractions of alcohol in vapor phase are close to unity at the pressures below 7.0 MPa for both systems. The pressures of liquid saturated lines of the liquid phase for methanol + glycerol and ethanol + glycerol systems are higher than that for the mixtures containing alcohol and biodiesel compound, methyl laurate or ethyl laurate.     

Vapor–liquid equilibria and phase densities at saturation of carbon dioxide + 1-butanol and carbon dioxide + 2-butanol from 313 to 363 K

Experimental vapor–liquid equilibria for the systems carbon dioxide + 1-butanol and carbon dioxide + 2-butanol were obtained from 313 to 363 K via a static-analytic set-up. A vibrating U-tube densitometer was coupled to this apparatus to perform simultaneous measurements of both saturated densities of the vapor and liquid phases. The suitability of this apparatus was checked by comparing the experimental vapor–liquid equilibrium and saturated density results with the literature data. The experimental vapor–liquid equilibrium data were correlated using the Peng–Robinson equation of state coupled to the Wong–Sandler mixing rules with good agreement; however densities using the same model were not satisfactorily represented.     

Vapor–liquid equilibrium data for the nitrogen + n-octane system from (344.5 to 543.5) K and at pressures up to 50 MPa

A static-analytical apparatus with visual sapphire windows and pneumatic capillary samplers has been used to obtain new vapor–liquid equilibrium data for the N₂ + n-octane system over the temperature range from (344.5 to 543.5) K and at pressures up to 50 MPa. Equilibrium phase compositions and vapor–liquid equilibrium ratios are reported. The new results were compared with solubility data reported by other authors. The comparison showed that the solubility data reported in this work at 344.5 K are in good agreement with those determined by others at 344.3 K. The experimental data were modeled with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature-independent interaction parameter. Results from the modeling effort showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the N₂ + n-octane system.     

Vapor–liquid equilibria and density measurement for binary mixtures of o-xylene + NMF, m-xylene + NMF and p-xylene + NMF at 333.15 K, 343.15 K and 353.15 K from 0 kPa to 101.3 kPa

Isothermal vapor–liquid equilibria at 333.15 K, 343.15 K and 353.15 K for three binary mixtures of o-xylene, m-xylene and p-xylene individually mixed with N-methylformamide (NMF), have been obtained at pressures ranged from 0 kPa to 101.3 kPa over the whole composition range. The Wilson, NRTL and UNIQUAC activity coefficient models have been employed to correlate experimental pressures and liquid mole fractions. The non-ideal behavior of the vapor phase has been considered by using the Peng–Robinson equation of state in calculating the vapor mole fraction. Liquid and vapor densities were measured by using two vibrating tube densitometers. The excess molar volumes of the liquid phase were also determined. Three systems of o-xylene + NMF, m-xylene + NMF and p-xylene + NMF mixtures present large positive deviations from the ideal solution and belong to endothermic mixings because their excess Gibbs energies are positive. Temperature dependent intermolecular parameters in the NRTL model correlation were finally obtained in this study.     

Isobaric vapor–liquid equilibrium for binary mixtures of 1-hexene + n-hexane and cyclohexane + cyclohexene at 30, 60 and 101.3 kPa

Consistent vapor–liquid equilibria (VLE) data were determined for the binary systems 1-hexene + n-hexane and cyclohexane + cyclohexene at 30, 60 and 101.3 kPa, with the purpose of studying the influence of the pressure in the separation of these binary mixtures. The two systems show a small positive deviation from ideality and do not present an azeotrope. VLE data for the binary systems have been correlated by the Wilson, UNIQUAC and NRTL equations with good results and have been predicted by the UNIFAC group contribution method.     

Vapor–liquid equilibrium measurement and modeling for the difluoromethane + pentafluoroethane + propane ternary mixture

Vapor–liquid equilibrium data for the difluoromethane (R32) + pentafluoroethane (R125) + propane (R290) ternary mixture were measured at 5 isotherms between 263.15 K and 323.15 K. The measurement was carried out using a circulation-type apparatus recently developed, which was validated with binary mixtures. With binary interaction parameters obtained for the three corresponding binary mixtures, VLE modeling and prediction were performed for the ternary mixture using the Peng–Robinson equation of state with the classical mixing rules and MHV1 mixing rules. Hou's group contribution model for VLE of new refrigerant mixtures was further tested with the experimental data for the ternary system. The predicted pressure and vapor phase composition were compared with experimental ones.     

High pressure vapor–liquid equilibrium data for the systems carbon dioxide/2-methyl-1-propanol and carbon dioxide/3-methyl-1-butanol at 288.2, 303.2 and 313.2 K

In this work, we report vapor–liquid equilibrium data for the systems carbon dioxide (CO₂)/iso-butanol and CO₂/iso-pentanol at 288.2, 303.2 and 313.2 K, and for pressures up to the critical point. The interaction parameters for the Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOS) that best fit the experimental results are also given.     

Vapor–liquid equilibrium measurements and modeling of the n-butane + ethanol system from 323 to 423 K

Vapor–liquid equilibrium (VLE) data are presented for the n-butane + ethanol system in the temperature range from 323 to 423 K. Measurements were performed using a “static-analytic” apparatus, equipped with two electromagnetic ROLSI™ capillary samplers, and thermally regulated via an air bath. This work presents vapor compositions which have not been explicitly measured previously. The modeling of the data was performed using two models: the Peng–Robinson equation of state with the Wong and Sandler mixing rule and NRTL excess function (PR/WS/NRTL); and the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state. To assess the effect of dipole–dipole interactions present, a dipolar contribution developed by Jog and Chapman (1999) [20] was tested with the second model. Temperature dependent binary interaction parameters have been adjusted to the new data. The PR/WS/NRTL equation of state shows good correlation with the results, while the PC-SAFT is slightly less accurate.     

Liquid–liquid equilibria for water + 1-propanol/2-propanol + potassium chloride + cesium chloride quaternary systems at 298.1 ± 0.1 K

In this paper, we present the results of our study of the phase equilibria for two quaternary systems: water + 1-propanol/2-propanol + potassium chloride (KCl) + cesium chloride (CsCl) at 298.1 ± 0.1 K. We also produced the binodal curves and tie-lines at different KCl/CsCl mass-fraction ratios, and produced integrated phase diagrams for the quaternary systems. We also discuss the solvation abilities of KCl and CsCl, and the effect of the polarity of the organic solvent on the liquid–liquid equilibrium. We compared the experimental tie-lines derived for the quaternary systems with values predicated by modifying the Eisen–Joffe equation. The model produced satisfactory results.     

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.