(Liquid + liquid) equilibria of the quaternary system methanol + isooctane + cyclohexane + benzene at T = 303.15 K

Tie line data of the ternary system {methanol + isooctane + cyclohexane} were obtained at T = 303.15 K. A quaternary system containing these three compounds and benzene was also studied at the same temperature, while data for {methanol + benzene + cyclohexane} and {methanol + benzene + isooctane} were taken from literature. In order to obtain the binodal surface of the quaternary system, four quaternary sectional planes with several cyclohexane/isooctane ratios were studied. The distribution of benzene between both phases was also analysed. Ternary experimental results were correlated with the UNIQUAC and NRTL equations and compared with predictions using the UNIFAC group contribution method.     

Isobaric vapor–liquid equilibria of 1,1-dimethylethoxy-butane + methanol or ethanol + water at 101.32 kPa

Isobaric vapor–liquid equilibrium data (VLE) at 101.325 kPa have been determined in the miscible region for 1,1-dimethylethoxy-butane (BTBE) + methanol + water and 1,1-dimethylethoxy-butane (BTBE) + ethanol + water ternary systems, and for their constituent binary systems, methanol + BTBE and ethanol + BTBE. Both binary systems show an azeotrope at the minimum boiling point. In the ternary system BTBE + methanol + water no azeotrope has been found, however, the system BTBE + ethanol + water might form a ternary azeotrope near the top of the binodal. Thermodynamically consistent VLE data have been satisfactorily correlated using the UNIQUAC, NRTL and Wilson equations for the activity coefficient of the liquid phase. Temperature and vapor phase compositions have been compared with those calculated by the group-contribution methods of prediction ASOG, and the original and modified UNIFAC. Predicted values are not in good agreement with experimental values.     

(Liquid + liquid) equilibria of {heptane + xylene + N-formylmorpholine} ternary system

(Liquid + liquid) equilibrium (LLE) data for ternary system {heptane (1) + m-xylene (2) + N-formylmorpholine (3)} have been determined experimentally at temperatures ranging from 298.15 K to 353.15 K. Complete phase diagrams were obtained by determining solubility and tie-line data. Tie-line compositions were correlated by Othmer-Tobias and Bachman methods. The universal quasichemical activity coefficient (UNIQUAC) and The non-random two liquids equation (NRTL) were used to correlate the phase equilibrium in the system using the interaction parameters determined from experimental data. It is found that UNIQUAC and NRTL used for LLE could provide a good correlation. Distribution coefficients, separation factors, and selectivity were evaluated for the immiscibility region.     

Phase equilibria of (water + levulinic acid + dibasic esters) ternary systems

Liquid–liquid equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {(water (1) + levulinic acid (2) + dimethyl succinate or dimethyl glutarate or dimethyl adipate (3)} at 298.15 K and 101.3 ± 0.7 kPa. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. The LLE data were correlated fairly well with UNIQUAC and NRTL models, indicating the reliability of the UNIQUAC and NRTL equations for these ternary systems. The best results were achieved with the NRTL equation, using non-randomness parameter (α = 0.3) for the correlation. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvents.     

Liquid-liquid equilibria for mixtures of (ethylene carbonate + aromatic hydrocarbon + cyclohexane)

Liquid-liquid equilibrium data for mixtures of (ethylene carbonate + benzene + cyclohexane) at temperatures 303.15 and 313.15 K and (ethylene carbonate + BTX + cyclohexane) at temperature 313.15 K are reported, where the BTX is benzene, toluene and m-xylene. The compositions of liquid phases at equilibrium were determined by gas liquid chromatography. The selectivity factors and partition coefficients of ethylene carbonate for the extraction of benzene, toluene and m-xylene from (ethylene carbonate + BTX + cyclohexane) are calculated and presented. The obtained results are compared with the selectivity factors and partition coefficients of ethylene carbonate for the extraction of benzene from (ethylene carbonate + benzene + cyclohexane). The liquid-liquid equilibrium data were correlated with the UNIQUAC and NRTL activity coefficient models. The phase diagrams for the studied mixtures are presented and the correlated tie line results have been compared with the experimental data. The comparisons indicate the applicability of the UNIQUAC and NRTL activity coefficients model for liquid-liquid equilibrium calculations of the studied mixtures. The tie line data of the studied mixtures also were correlated using the Hand method.     

Liquid–liquid equilibria for mixtures containing water,methanol, fatty acid methyl esters,and glycerol

The liquid–liquid equilibrium (LLE) data, including tie-lines and phase boundaries, were measured for the ternary systems of water + methanol + methyl oleate, water + methanol + methyl linoleate, glycerol + methanol + methyl oleate, and glycerol + methanol + methyl linoleate at temperatures from 298.2 K to 318.2 K under atmospheric pressure. All the LLE data follow the Othmer-Tobias equation. Each ternary system behaves type-I LLE. The areas of two-liquid coexistence region decrease with increasing temperature. The experimental data were applied to test the validity of the UNIFAC model and its modified versions, including UNIFAC-LLE and UNIFAC-Dortmund. The LLE data were also correlated with the NRTL and the UNIQUAC models. The UNIQUAC model yielded better results.     

Measurement and prediction of tie-line data for mixtures of (water + 1-propanol + diisopropyl ether): LLE diagrams as a function of temperature

Tie-line data for ternary system of (water + 1-propanol + diisopropyl ether (DIPE)) were determined at T = (298.2, 308.2 and 313.2) K under atmospheric conditions. The ternary system exhibited type-I LLE behavior, as (DIPE + water) is the only liquid pair that is partially miscible. The experimental data for this system were predicted with the UNIFAC model with a root mean square deviation of 2.64%. The reliability of the experimental tie-line data was determined through the Othmer–Tobias and Hand plots. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvents. The influence of temperature effect on the equilibrium characteristics and separation factor was found to be significant at the temperatures studied.     

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 + propionic acid + cyclohexanone) at several temperatures

(Liquid + liquid) equilibrium (LLE) data for (water + propionic acid + cyclohexanone) were measured under atmospheric pressure and at T = (293.2, 298.2 and 303.2) K. Phase diagrams were obtained by determining solubility and tie-line data. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated over the immiscibility regions.     

Measurement and correlation of vapor–liquid equilibria for methanol + methyl laurate and methanol + methyl myristate systems near critical temperature of methanol

A flow-type method was adopted to measure the vapor–liquid equilibria for methanol + methyl laurate and methanol + methyl myristate systems at 493–543 K, near the critical temperature of methanol (T_c = 512.64 K), and 2.16–8.49 MPa. The effect of temperature and fatty acid methyl esters to the phase behavior was discussed. The mole fractions of methanol in liquid phase are almost the same for both systems. In vapor phase, the mole fractions of methanol are very close to unity at all temperatures. The present vapor–liquid equilibrium data were correlated by PRASOG. A binary parameter was introduced to the combining rule of size parameter. The binary parameters of methanol + fatty acid methyl ester systems were determined by fitting the present experimental data. The correlated results are in good agreement with the experimental data. The vapor–liquid equilibria for methanol + methyl laurate + glycerol and methanol + methyl myristate + glycerol ternary systems were also predicted using the methanol + fatty acid methyl ester binary parameters. The mole fractions of methanol in vapor phase are around unity even if glycerol is included in the systems.     

(Liquid + liquid) equilibria of (water + propionic acid + alcohol) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end composition were examined for mixtures of {water (1) + propionic acid (2) + octanol or nonanol or decanol or dodecanol (3)} at T = 298.15 K and 101.3 ± 0.7 kPa. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of the (water + acetic acid + dibasic esters mixture) system

(Liquid + liquid) equilibrium (LLE) data for the {water + acetic acid + dibasic esters mixture (dimethyl adipate + dimethyl glutarate + dimethyl succinate)} system have been determined experimentally at T = (298.2, 308.2, and 318.2) K. Complete phase diagrams were obtained by determining solubility curve and tie-line data. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. The UNIFAC model was used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data between CH₂, CH₃COO, CH₃, COOH, and H₂O functional groups. Distribution coefficients and separation factors were compared with previous studies.     

Phase equilibrium for the systems diisopropyl ether,isopropyl alcohol + 2,2,4-trimethylpentane and +n-heptane at 101.3 kPa

Consistent vapour–liquid equilibrium data for the ternary systems diisopropyl ether + isopropyl alcohol + 2,2,4-trimethylpentane and diisopropyl ether + isopropyl alcohol + n-heptane are reported at 101.3 kPa. The vapour–liquid equilibrium data have been correlated by Wilson, NRTL and UNIQUAC equations. The ternary systems do not present ternary azeotropes.     

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.     

(Liquid + liquid) equilibria of (water + linalool + limonene) ternary system at T = (298.15, 308.15, and 318.15) K

(Liquid + liquid) equilibrium (LLE) data for {water (1) + linalool (2) + limonene (3)} ternary system at T = (298.15, 308.15, and 318.15 ± 0.05) K are reported. The organic chemicals were quantified by gas chromatography using a flame ionisation detector while water was quantified using a thermal conductivity detector. The effect of the temperature on (liquid + liquid) equilibrium is determined and discussed. Experimental data for the ternary mixture are compared with values calculated by the NRTL and UNIQUAC equations, and predicted by means of the UNIFAC group contribution method. It is found that the UNIQUAC and NRTL models provide a good correlation of the solubility curve at these three temperatures, while comparing the calculated values with the experimental ones, the best fit is obtained with the NRTL model. Finally, the UNIFAC model provides poor results, since it predicts a greater heterogeneous region than experimentally observed.     

Densities, refractive indices and speeds of sound of the ternary mixtures (dimethyl carbonate + methanol + ethanol) and (dimethyl carbonate + methanol + 1-propanol) at T=298.15 K

Density, refractive index and speed of sound at T=298.15 K and atmospheric pressure have been measured over the entire composition range for (dimethyl carbonate (DMC) + methanol + ethanol) and (DMC + methanol + 1-propanol). Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems have been calculated. The calculated quantities are further fitted to the Cibulka equation to estimate the ternary fitting parameters. Standard deviations from the regression lines are shown.     

Liquid–liquid equilibria for quaternary mixtures of nonane + undecane + (benzene or toluene or m-xylene) + sulfolane at 298.15 and 313.15 K

Liquid–liquid equilibrium (LLE) data were measured for three quaternary systems containing sulfolane, nonane + undecane + benzene + sulfolane, nonane + undecane + toluene + sulfolane and nonane + undecane + m-xylene + sulfolane, at T = 298.15 and 313.15 K and ambient pressure. The experimental quaternary liquid–liquid equilibrium data have been satisfactorily represented by using NRTL and UNIFAC-LLE models for the activity coefficient. The calculated compositions based on the NRTL model were found to in a better agreement with the experiment than those based on the UNIFAC-LLE model.     

Investigation on isobaric vapor liquid equilibrium for acetic acid + water + (n-propyl acetate or iso-butyl acetate)

Isobaric vapor-liquid equilibrium (VLE) data for acetic acid + water, acetic acid + n-propyl acetate, acetic acid + iso-butyl acetate, acetic acid + water + n-propyl acetate, acetic acid + water + iso-butyl acetate are measured at 101.33 kPa with a modified Rose still. The nonideal behavior in vapor phase caused by the association of acetic acid are corrected by the chemical theory and Hayden-O’Connell method, and analyzed by calculating the second virial coefficients and apparent fugacity coefficients. The VLE data for acetic acid + water, acetic acid + n-propyl acetate, and acetic acid + iso-butyl acetate are correlated through the NRTL and UNIQUAC models using the nonlinear least square method. The obtained NRTL model parameters are used to predict the ternary VLE data. The ternary predicted values obtained in this way agree well with the experimental values.     

Phase behavior of the system hyperbranched polyglycerol + methanol + carbon dioxide

Phase equilibrium data have been measured for the ternary system hyperbranched polyglycerol + methanol + carbon dioxide at temperatures of 313–450 K and pressures up to 13.5 MPa. Phase changes were determined according to a synthetic method using the Cailletet setup. At elevated temperatures the system shows a liquid–liquid–vapor region with lower solution temperatures. Besides the vapor–liquid and liquid–liquid equilibria, the vapor–liquid to vapor–liquid–liquid and vapor–liquid–liquid to liquid–liquid phase boundaries are reported at different polymer molar masses and can serve as test sets for thermodynamic models. A distinct influence of the polymer molar mass on the vapor–liquid equilibrium can be noticed and indicates the existence of structural effects due to the polymer branching. Modeling the systems with the PCP-SAFT equation of state confirms these findings.     

Liquid phase equilibria of (water + phosphoric acid + 1-butanol or butyl acetate) ternary systems at T = 308.2 K

(Liquid + liquid) equilibria and tie lines for the ternary systems of (water + phosphoric acid + 1-butanol) and (water + phosphoric acid + butyl acetate) were measured at T = 308.2 K. The experimental ternary (liquid + liquid) equilibrium data were correlated with the UNIQUAC model. The reliability of the experimental tie lines was confirmed using Othmer-Tobias correlation. The average root-mean-square deviation (RMSD) values of (water + phosphoric acid + 1-butanol) and (water + phosphoric acid + butyl acetate) systems were 2.17% and 2.16%, respectively. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvents. The results show that butyl acetate may be considered as a reliable organic solvent for the extraction of phosphoric acid from aqueous solutions.