Quaternary liquid–liquid equilibria for systems of {(water + methanol or ethanol) + m-xylene + n-dodecane}

Liquid–liquid equilibrium (LLE) data were determined for the quaternary systems of {(water + methanol or ethanol) + m-xylene + n-dodecane} at three temperatures 298.15, 303.15 and 313.15 K and atmospheric pressure. The composition of liquid phases at equilibrium was determined by gas–liquid chromatography and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of the solvent are calculated and compared. The phase diagrams for the quaternary systems including both the experimental and correlated tie lines are presented.     

(Liquid + liquid) equilibria for ternary mixtures of (ethylene glycol + toluene + n-octane)

Tie-line data for ternary systems of (ethylene glycol + toluene + n-octane) at three temperatures (295.15, 301.15, and 307.15) K are reported. The compositions of liquid phases at equilibrium were determined and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of ethylene glycol are calculated and compared to suggest which ethylene glycol is more suitable for extracting of toluene from n-octane. The phase diagrams for the studied ternary mixtures including both the experimental and correlated tie lines are presented. From the phase diagrams and the selectivity factors, it is concluded that ethylene glycol may be used as a suitable solvent in extraction of toluene from n-octane mixtures.     

Phase equilibria for liquid mixtures of (benzonitrile + a carboxylic acid + water) atT = 298.15 K

(Liquid  +  liquid) equilibrium data are presented for mixtures of {benzonitrile(1)  +  acetic acid or propanoic acid or butanoic acid or 2-methylpropanoic acid or pentanoic acid or 3-methylbutanoic acid(2)  +  water(3)} atT =  298.15 K. The relative mutual solubility of each of the carboxylic acids is higher in the benzonitrile layer than in the aqueous layer. The influence of 3-methylbutanoic acid, pentanoic acid, 2-methylpropanoic acid, and butanoic acid on the solubility of the hydrocarbons in benzonitrile is greater than that of the acetic and propanoic acids. Three three-parameter equations have been fitted to the binodal curve data. These equations are compared and discussed in terms of statistical consistency. The NRTL and UNIQUAC models were used to correlate the experimental tie lines and to calculate the phase compositions of the ternary systems. The NRTL equation fitted the experimental data far better than the UNIQUAC equation. Selectivity values for solvent separation efficiency were derived from the tie line data.     

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid + water, acetic acid + methyl ethyl ketone (MEK), MEK + isopropyl acetate, acetic acid + MEK + water and acetic acid + MEK + isopropyl acetate + water are measured at 101.33 kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in vapor phase due to the associating effect of acetic acid. Combined with Hayden–O’Connell (HOC) equation, the VLE data of the measured binary systems for acetic acid + water, acetic acid + MEK and MEK + isopropyl acetate are correlated by the NRTL and UNIQUAC models. The NRTL model parameters obtained from correlating data of binary system are used to predict the VLE data of the ternary and quaternary systems, and the predicted values obtained in this way agree well with the experimental values.     

Equilibrium data for systems composed by cottonseed oil + commercial linoleic acid + ethanol + water + tocopherols at 298.2 K

The present paper reports liquid–liquid equilibrium data for the system refined cottonseed oil + commercial linoleic acid + ethanol + water at 298.2 K. The experimental data were used for adjusting parameters of the NRTL and UNIQUAC models. The global deviations between calculated and experimental concentrations were 0.80% for the NRTL model and 1.44% for the UNIQUAC equation. The influence of the solvent on the distribution coefficient of tocopherols was also studied. UNIQUAC and NRTL interaction parameters between tocopherols and the other pseudocomponents were determined assuming that the nutraceutical compound is present at infinite dilution in the liquid–liquid equilibrium system. The obtained parameter set enables the simulation of liquid–liquid extractors.     

Measurement and correlation of (liquid + liquid) equilibrium of the azeotrope (cyclohexane + 2-butanone) with different ionic liquids at T = 298.15 K

Experimental densities, speeds of sound, and refractive indices of the binary mixtures of 2-butanone with cyclohexane and OMIM PF₆ (1-methyl-3-octylimidazolium hexafluorophosphate) were determined from T = (293.15 to 303.15) K, since they are necessary to determine the (liquid + liquid) equilibrium. Excess molar volumes, changes of refractive index on mixing, and deviations in isentropic compressibility for the above systems were calculated. Experimental (liquid + liquid) equilibrium of the ternary mixtures {cyclohexane + 2-butanone + 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIM PF₆)} and (cyclohexane + 2-butanone + OMIM PF₆) were carried out to assess the suitability of HMIM PF₆ and OMIM PF₆ as azeotrope breaker of the mixture cyclohexane and 2-butanone. Selectivity and distribution ratio values, derived from the tie lines data, were presented in order to analyze the best separation solvent in a liquid extraction process. Experimental (liquid + liquid) equilibrium data were compared with the correlated values obtained by means of the NRTL and UNIQUAC models.     

Vapor–liquid equilibria and interfacial tensions for the ternary system acetone + 2,2′-oxybis[propane] + cyclohexane and its constituent binary systems

Isobaric vapor–liquid equilibrium data have been measured for the ternary system acetone + 2,2′-oxybis[propane] + cyclohexane, and its constituent binaries at 94 kPa and in the temperature range 324–350 K in a vapor–liquid equilibrium still with circulation of both phases. The dependence of the interfacial tensions of these mixtures on concentration was also determined at atmospheric pressure and 303.15 K, using the maximum bubble pressure technique.From the experimental results, it follows that both the ternary and binary mixtures exhibit positive deviations from ideal behavior and, additionally, azeotropy is present for the binaries that contain acetone. The application of a model-free approach allows conclusions about the reliability of the present vapor–liquid equilibrium data for all the indicated mixtures. Furthermore, the determined interfacial tensions exhibit negative deviation from linear behavior for all the analyzed mixtures, and aneotropy is observed for the acetone + cyclohexane mixture.The vapor–liquid equilibrium data of the binary mixtures were well correlated using the NRTL, Wilson and UNIQUAC equations. In a similar manner, the interfacial tensions of the binary mixtures were smoothed using the Redlich–Kister equation. Scaling of these models to the ternary mixture allows concluding that both the vapor–liquid equilibrium data and the interfacial tensions can be reasonably predicted from binary contributions.     

Determination and correlation of liquid–liquid equilibria for the (water + carboxylic acid + dimethyl maleate) ternary systems at T = 298.2 K

(Liquid–liquid) equilibrium (LLE) data for the ternary systems of {water + carboxylic acid (formic, acetic, propionic or butyric acid) + dimethyl maleate} were measured at T = 298.2 K and atmospheric pressure. Selectivity values for solvent separation efficiency were derived from the tie-line data. A comparison of the extracting capabilities of the solvent was made with respect to distribution coefficients, separation factors, and solvent-free selectivity bases. The reliability of the data was ascertained from Othmer–Tobias plots. The experimental data were correlated using the UNIQUAC and NRTL (α = 0.2) equations, and the binary interaction parameters were reported. The phase diagrams for the ternary mixtures including both the experimental and calculated tie-lines were presented.     

(Liquid + liquid) equilibria for ternary mixtures of (methanol or ethanol + toluene or m-xylene + n-dodecane)

(Liquid + liquid) equilibrium (LLE) results for the ternary mixtures of (methanol or ethanol + toluene or m-xylene + n-dodecane) at three temperatures (298.15, 303.15 and 313.15) K are reported. The compositions of liquid phases at equilibrium were determined by g.l.c. measurements and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of methanol and ethanol are calculated and compared to suggest which alcohol is more suitable for extracting the aromatic hydrocarbons (toluene or m-xylene) from n-dodecane. The phase diagrams for the ternary mixtures including both the experimental and correlated tie lines are presented. From the phase diagrams and the selectivity factors it is concluded that methanol has a higher efficiency as a solvent in extraction of aromatic hydrocarbon from alkane mixtures.     

Isobaric (vapour + liquid) equilibria for the (1-pentanol + propionic acid) binary mixture at (53.3 and 91.3) kPa

Isobaric (vapour + liquid) equilibrium measurements have been reported for the binary mixture of (1-pentanol + propionic acid) at (53.3 and 91.3) kPa. Liquid phase activity coefficients were calculated from the equilibrium data. The thermodynamic consistency of the experimental results was checked using the area test and direct test methods. According to these criteria, the measured (vapour + liquid) equilibrium results were found to be consistent thermodynamically. The obtained results showed a maximum boiling temperature azeotrope at both pressures studied. The measured equilibrium results were satisfactorily correlated by the models of Wilson, UNIQUAC, and NRTL activity coefficients. The results obtained indicate that the performance of the NRTL model is superior to the Wilson and UNIQUAC models for correlating the measured isobaric (vapour + liquid) equilibrium data.     

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.     

Isobaric vapor–liquid phase equilibria for the binary systems of tert-butanol + 2-ethyl-1-hexanol and n-butanol + 2-ethyl-1-hexanol

Isobaric vapor–liquid equilibria for the binary mixtures of tert-butanol (TBA) + 2-ethyl-1-hexanol and n-butanol (NBA) + 2-ethyl-1-hexanol were experimentally investigated at atmospheric pressure in the temperature range of 353.2–458.2 K. The raw experimental data were correlated using the UNIQUAC and NRTL models and used to estimate the interaction parameters between each pair of components in the systems. The experimental activity coefficients were obtained using the gas chromatographic method and compared with the calculated data obtained from these equilibrium models. The results show that UNIQUAC model gives better correlation than NRTL for these binary systems. The liquid–liquid extraction of TBA from aqueous solution using 2-ethyl-1-hexanol was demonstrated by simulation and the variation of separation factor of TBA at several temperatures was reported.     

Liquid–liquid equilibria for n-alkanes (C12, C14, C17) + propylbenzene + NMP mixtures at temperatures between 298 and 328 K

Liquid–liquid equilibria for three ternary systems: dodecane, or tetradecane, or heptadecane + propylbenzene + NMP was studied over a temperature range of 298–328 K. The three systems studied exhibit type I liquid–liquid phase diagram. The effect of temperaure and n-alkane chain length upon solubility, selectivity, and distribution coefficient were investigated experimentally. The experimental results were regressed to estimate the interaction parameters between each of the three pairs of components for the UNIQUAC and the NRTL models as a function of temperature. Both models satisfactorily correlate the experimental data, however the UNIQUAC fit was slightly better than that obtained with the NRTL model. The values of distribution coefficient and selectivity were predicated from the equilibrium data.     

Isobaric vapour–liquid equilibria for binary systems of 2-butanone with ethanol, 1-propanol, and 2-propanol at 20 and 101.3 kPa

Consistent isobaric vapour–liquid equilibrium data have been measured for 2-butanone + ethanol, 2-butanone + 1-propanol, and 2-butanone + 2-propanol at 20 and 101.3 kPa. The binary systems 2-butanone + ethanol and 2-butanone + 2-propanol present a minimum boiling azeotrope at both pressures, and show that the azeotropic compositions is strongly dependent on pressure. The equilibrium data were correlated using the Wilson, NRTL, and UNIQUAC models for which the parameters are reported.     

(Liquid + liquid) equilibria of three ternary systems: (heptane + benzene + N-formylmorpholine), (heptane + toluene + N-formylmorpholine), (heptane + xylene + N-formylmorpholine) from T = (298.15 to 353.15) K

(Liquid + liquid) equilibrium (LLE) data for ternary systems: (heptane + benzene + N-formylmorpholine), (heptane + toluene + N-formylmorpholine), and (heptane + xylene + N-formylmorpholine) 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 predict 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.     

(Liquid + liquid) equilibria for mixtures of (ethylene glycol + benzene + cyclohexane) at temperatures (298.15, 308.15, and 318.15) K

Experimental (liquid + liquid) equilibrium (LLE) data for a ternary system containing (ethylene glycol + benzene + cyclohexane) were determined at temperatures (298.15, 308.15, and 318.15) K and at atmospheric pressure. The experimental distribution coefficients and selectivity factors are presented to evaluate the efficiency of the solvent for extraction of benzene from cyclohexane. The effect of temperature in extraction of benzene from the (benzene + cyclohexane) mixture indicated that at lower temperatures the selectivity (S) is higher, but the distribution coefficient (K) is rather lower. The LLE results for the system studied were used to obtain binary interaction parameters in the UNIQUAC and NRTL models by minimizing the root mean square deviations (RMSD) between the experimental results and calculated results. Using the interaction parameters obtained, the phase equilibria in the systems were calculated and plotted. The NRTL model fits the (liquid + liquid) equilibrium data of the mixture studied slightly better. The root mean square deviations (RMSDs) obtained comparing calculated and experimental two-phase compositions are 0.92% for the NRTL model and 0.95% for the UNIQUAC model.     

Isothermal (vapour + liquid) equilibrium for binary mixtures of polyethylene glycol mono-4-nonylphenyl ether (PEGNPE) with methanol,ethanol, or 2-propanol

Saturated pressures of three binary systems of oligomeric polyethylene glycol mono-4-nonylphenyl ether (PEGNPE) with methanol, ethanol, and 2-propanol have been measured by using an autoclave (vapour + liquid) equilibrium (VLE) apparatus at temperatures ranging from (340 to 455) K and the oligomer content ranging from 0.100 to 0.400 in mole fraction. With a given feed composition, equilibrium pressures were measured at various temperatures to obtain VLE data. The experimental data were fitted to the Antoine equation and also correlated with activity coefficient models, the NRTL and the UNIQUAC. The correlation results showed good agreement between the calculated values and the experimental data. In general, the NRTL model yielded better results. Additionally, the solvent activities were evaluated from the experimental results and were compared with those from the NRTL and the UNIQUAC models.     

Isobaric (vapour + liquid) equilibria for the (1-propanol + 1-butanol) binary mixture at (53.3 and 91.3) kPa

In this work, isobaric (vapour + liquid) equilibrium data have been determined at (53.3 and 91.3) kPa for the binary mixtures of (1-propanol + 1-butanol). The thermodynamic consistency of the experimental values was checked by means the traditional area test and the direct test methods. According to the criteria for the test methods, the (vapour + liquid) equilibrium results were found to be thermodynamically consistent. The experimental values obtained were correlated by using the van Laar, Margules, Wilson, NRTL, and UNIQUAC activity-coefficient models. The binary interaction parameters of the activity-coefficient models have been determined and reported. They have been compared with those calculated by the activity-coefficient models. The average absolute deviation in boiling point and vapour-phase composition were determined. The calculated maximum average absolute deviations were 0.86 K and 0.0151 for the boiling point and vapour-phase composition, respectively. Therefore, it was shown that the activity-coefficient models used satisfactorily correlate the (vapour + liquid) equilibrium results of the mixture studied. However, the performance of the UNIQUAC model was superior to all other models mentioned.     

Binodal curve measurements for (water + propionic acid + dichloromethane) ternary system by cloud point method

The binodal (solubility) curves and tie line data for ternary systems of (water + propionic acid + dichloromethane) at 91.3 kPa and T = (277.15, 284.15, and 294.15) K are reported. The binodal curve results were determined by cloud point measurements method. A simple titration method has been used for determining of the concentration of propionic acid in the both liquid phases at equilibrium. The results obtained were successfully correlated with the UNIQUAC activity coefficient model. The deviations between experimental and calculated compositions in both phases for the ternary system using this model are reported. The partition coefficients of propionic acid and the selectivity factor of dichloromethane for extracting of propionic acid from water were calculated and are reported. The phase diagrams for the ternary system studied including both the experimental and correlated tie lines are presented.     

Isothermal (vapour + liquid) equilibria for the binary (cyclopentanone or cyclohexanone with 1,1,2,2-tetrachloroethane) systems at temperatures of (343.15, 353.15, and 363.15) K

The vapour pressure of pure components and isothermal (vapour + liquid) equilibrium data at temperatures of (343.15, 353.15, and 363.15) K for binary mixtures containing (cyclopentanone or cyclohexanone with 1,1,2,2-tetrachloroethane) are reported. Use has been made of an ebulliometer which allowed sampling from both phases in equilibrium. Both systems exhibit azeotrope with minimum pressure at all three temperatures. The experimental data were correlated using the Redlich–Kister, Wilson, NRTL and UNIQUAC models by means of maximum likelihood method. The systems show negative deviations from ideal behaviour.