Universal Quasichemical Activity Coefficient Research Articles

Liquid–liquid equilibria for ternary systems of dimethyl carbonate + C 1–C 4 alcohols + water at 298.15 K and atmospheric pressure

The ternary liquid–liquid equilibria (LLE) of the following systems were analytically determined at 298.15 K and atmospheric pressure using stirred and thermo-regulated cells: {dimethyl carbonate (DMC) + methanol + water}, {DMC + ethanol + water}, {DMC + 1-propanol + water}, {DMC + 2-propanol + water}, {DMC + 1-butanol + water} and {DMC + 2-butanol + water}. The experimental ternary LLE data were correlated with the non-random two liquid (NRTL) and UNIversal QUAsiChemical (UNIQUAC) activity coefficient models. In addition, the Bachman–Brown correlation was used to ascertain the reliability of the experimental data for each system.

Phase Equilibria Involved in the Extractive Distillation of Cyclohexane + Cyclohexene Using Diethyl Carbonate as an Entrainer

Isobaric vapor–liquid equilibrium (VLE) data at 100 kPa have been measured for the ternary system cyclohexane + cyclohexene + diethyl carbonate and two constituent binary systems: cyclohexane + diethyl carbonate and cyclohexene + diethyl carbonate. Both binary systems show moderate positive deviations from ideal behavior and do not present an azeotrope. The VLE data have been correlated by the Wilson, universal quasichemical activity coefficient (UNIQUAC), and nonrandom two-liquid (NRTL) equations. The ternary system does not present an azeotrope and is well-estimated from binary interaction parameters. A prediction with the universal functional activity coefficient (UNIFAC)-Dortmund method has been also obtained.

Determination and Correlation of Vapor–Liquid Equilibrium Data for the Ethyl Acetate + Hexamethyl Disiloxane System at 101.3 kPa

Vapor–liquid equilibrium (VLE) data of ethyl acetate (EAC) + hexamethyl disiloxane (HMDSO) system at 101.3 kPa were measured by using a double circulating VLE still. The thermodynamic consistency of the VLE data was examined by the Herrington method. Experimental data were correlated by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC) parameter models. All of the models were satisfactorily correlated with the VLE data. The result showed that the NRTL model was the most suitable one to represent experimental data satisfactorily, the system had a minimum temperature azeotrope at 350.31 K, and the mole azeotropic composition was 0.0330.

Isobaric Vapor–Liquid Equilibrium for Binary Systems of Toluene + Acrylic Acid, Toluene + Acetic Acid, and Cyclohexane + Acrylic Acid at 20 kPa

Vapor–liquid equilibrium (VLE) data for toluene + acrylic acid, toluene + acetic acid, and cyclohexane + acrylic acid systems have been determined at 20 kPa (absolute pressure) using a circulating VLE still. The Hayden and O'Connell equation has been used to account for the nonideality of the vapor phase. The experimental data were checked both with the Herington consistency test and point consistency test methods, which showed thermodynamic consistency. Only the toluene and acetic acid system presents an azeotrope at 20 kPa and 332.29 K with the mole fraction of toluene as 0.525. All equilibrium data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models to obtain the binary interaction parameters of these models using Aspen Plus commercial software to introduce them in the simulation model.

Measurement and Calculation of Liquid–Liquid Equilibria of Ternary and Quaternary Systems Containing Water, Propan-1-ol, and 2,2,4-Trimethylpentane (TMP) with 2,2′-Oxybis(propane) (DIPE) or Dimethyl Carbonate (DMC)

Liquid–liquid equilibrium data for quaternary systems of water + propan-1-ol + 2,2,4-trimethylpentane (TMP) + 2,2′-oxybis(propane) (DIPE) or dimethyl carbonate and ternary systems of water + propan-1-ol + TMP or DIPE or dimethyl carbonate (DMC) were measured at 298.15 K and ambient pressure. The experimental tie-line results were correlated with the modified and extended universal quasichemical (UNIQUAC) activity coefficient models both with ternary and quaternary parameters in addition to binary ones. Distribution coefficients were calculated to evaluate the solubility of DMC or DIPE in aqueous and organic phases. The phase diagrams for the ternary and quaternary systems measured in this work including both the experimental and the correlated tie lines are presented.

Ternary Liquid–Liquid Equilibria of Water + Prop-2-enoic Acid + Isobutyl Ethanoate at Different Temperatures

To screen the proper solvent for separating prop-2-enoic acid aqueous solution by the method of extraction followed by heterogeneous azeotropic distillation, the liquid–liquid equilibria (LLE) data for the ternary system water + prop-2-enoic acid + isobutyl ethanoate at (293.15, 303.15, and 313.15) K were measured at atmospheric pressure. The reliability of the experimental LLE data was ascertained through Othmer–Tobias and Hand correlations. The LLE phase diagrams at different temperatures for the ternary system were given. Distribution coefficients and separation factors were calculated from the LLE data. The thermodynamic models of nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) were used to correlate the data of the ternay system. The calculated values from both models agree well with the experimental values.

Isobaric (vapour + liquid) equilibria for sulfolane with toluene, ethylbenzene, and isopropylbenzene at 101.33 kPa

Isobaric (vapour + liquid) equilibrium data have been measured for the (toluene + sulfolane), (ethylbenzene + sulfolane), and (isopropylbenzene + sulfolane) binary systems with a modified Rose-Williams still at 101.33 kPa. The experimental data of binary systems were well correlated by the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models for the liquid phase. All the experimental results passed the thermodynamic consistency test by the Herington method. Furthermore, the model UNIFAC (Do) group contribution method was used. Sulfolane is treated as a group (TMS), the new group interaction parameters for CH 2–TMS, ACH–TMS and ACCH 2–TMS were regressed from the VLE data of (toluene + sulfolane) and (ethylbenzene + sulfolane) binary systems. Then these group interaction parameters were used to estimate phase equilibrium data of the (isopropylbenzene + sulfolane) binary system. The results showed that the estimated data were in good agreement with the experimental values. The maximum and average absolute deviations of the temperature were 4.50 K and 2.39 K, respectively. The maximum and average absolute deviations for the vapour phase compositions of isopropylbenzene were 0.0237 and 0.0137, respectively.

Liquid–Liquid Phase Equilibria of 1-Propanol + Water + n-Alcohol Ternary Systems at 298.15 K and Atmospheric Pressure

Liquid–liquid equilibrium (LLE) data for the ternary systems 1-propanol + water + n-alcohols (1-pentanol, 1-hexanol, 1-octanol, 1-nonanol, 1-decanol, or 1-dodecanol) were determined at 298.15 K and atmospheric pressure. The n-alcohols from 1-pentanol up to 1-dodecanol can be used as extraction solvents for the separation of 1-propanol from aqueous solutions. The miscibility curves, the conode lines, and the plait points were obtained. The phase diagrams for all of these systems are of type I in according to Trayball classification. The Othmer–Tobias and Hand equations, used to verify the quality of the experimental data, give similar and generally good results for all of the systems. The experimental ternary LLE data were correlated with the universal quasichemical activity coefficient (UNIQUAC) model which represents satisfactorily the obtained experimental data. Distribution coefficients (Di) and separation factors (S) were calculated from tie-line data to evaluate the extracting capability of the solvents, which increases with increasing alcohol chain length.

Liquid−Liquid Equilibria for the Quaternary System Water (1) + Acrylic Acid (2) + Acetic Acid (3) + Cyclohexane (4) at (293.15, 303.15, and 313.15) K

Liquid−liquid equilibria (LLE) data for the quaternary system water + acrylic acid + acetic acid + cyclohexane at (293.15, 303.15, and 313.15) K have been measured at atmospheric pressure. The reliability of the experimental LLE data was ascertained through Othmer−Tobias and Bachman correlations. The pseudoternary phase diagrams at different temperatures for the quaternary system were given. The nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were used to correlate the data of the quaternary system. The calculated values from both models agree well with the experimental values.

Liquid−Liquid and Vapor−Liquid−Liquid Equilibrium of the 2-Butanone + 2-Butanol + Water System

Liquid−liquid phase equilibrium (LLE) data have been measured for the ternary system 2-butanone + 2-butanol + water at (293.25, 313.15, 323.15, and 333.15) K. Experimental results show the extreme phase sensitivity of this system to temperature. At (293.15 and 313.15) K the ternary system has two separate biphasic regions, while at (323.15 and 333.15) K the system has only one region of immiscibility. The nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were applied to correlate the ternary system at (323.15 and 333.15) K; the interaction parameters obtained from both models successfully correlated the equilibrium compositions. Moreover, isobaric vapor−liquid−liquid equilibrium (VLLE) is measured for this ternary mixture at 101.3 kPa. The experimental data were compared with the estimation from LLE binary interaction parameters using NRTL and UNIQUAC models and with the prediction of universal functional activity coefficient (UNIFAC) model.

Liquid−Liquid Equilibrium, Solid−Liquid Equilibrium, Densities, and Refractivity of a Water, Chloroform, and Acetylacetone Mixture

Molybdenum is chemically combined with other elements and usually extracted from acid leaching a residual solution of molybdenite. Understanding the behavior of the solvents is important for the optimization of the separation procedures. Therefore, binary and ternary liquid−liquid equilibria (LLE) were measured for a mixture of chloroform, acetylacetone, and water at (293.15 to 333.15) K and atmospheric pressure (101.3 ± 0.7 kPa). The solid−liquid equilibrium (SLE) between chloroform and acetylacetone was also determined by visual techniques. This system has a single eutectic point. The experimental LLE and SLE data were well-correlated by the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models. In addition, the excess molar volume (VE) and refractivity (nD) for the binary chloroform + acetylacetone mixture were measured at 298.15 K over the entire composition range. The experimental data were satisfactorily fit using the Redlich−Kister polynomial.

Correction toP, ρ,TMeasurements and Isobaric Vapor–Liquid Equilibria of the 1,3,3-Trimethyl-2-oxabicycle[2,2,2]octane + Propan-1-ol Mixture: Cubic and Statistical Associating Fluid Theory-Based Equation of State Analysis

Densities measured at pressures from (20 to 40) MPa and the temperatures (283.15, 298.15, 313.15, and 328.15) K and isobaric (vapor + liquid) equilibrium (VLE) at pressures of (33.33, 66.66, and 101.33) kPa are reported for the mixture {1,8-cineole(1,3,3-trimethyl-2-oxabicycle[2,2,2]octane) + propan-1-ol} in the whole composition range. Excess molar volumes, isobaric thermal expansions, and isothermal compressibilities were calculated from the density data. VLE data were correlated by means of three activity coefficient models [Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC)], and their thermodynamic consistency was determined. Four equations of state (EOS), namely, the Peng−Robinson, the Patel−Teja, statistical associating fluid theory (SAFT), and perturbed-chain statistical associating fluid theory (PC-SAFT), were used first to predict (interaction parameters, kij, equal to zero) both the density and the VLE behavior of the system and second to correlate t...

Solubilities of Benzene Carboxylic Acids in Isobutyl Acetate from (299.73 to 353.15) K

Solubilities of benzoic acid, p-methylbenzoic acid, o-phthalic acid, m-phthalic acid, and terephthalic acid in isobutyl acetate were measured in the temperature range from (299.73 to 353.15) K. The solubility data showed notable distinction in terms of different orders of magnitude. The experimental data were correlated by the universal quasichemical activity coefficient (UNIQUAC) model and the Wilson model. Generally, the UNIQUAC model was slightly superior to the Wilson model.

Measurement and Correlation of Vapor−Liquid Equilibrium Data for β-Pinene + p-Cymene + (S)-(−)-Limonene at Atmospheric Pressure

Vapor−liquid equilibrium (VLE) data for binary systems of β-pinene + p-cymene and β-pinene + (S)-(−)-limonene and the ternary system of β-pinene + p-cymene + (S)-(−)-limonene were measured at 100.7 kPa using the modified Ellis equilibrium still. The experimental data of binary systems were tested for thermodynamic consistency with the method of Herington and point-to-point test of Van Ness. The parameters of four solution models—Wilson, nonrandom two-liquid (NRTL), universal quasichemical activity coefficient (UNIQUAC), and Liebermann−Fried—were calculated with the aid of the least-squares method to minimize an objective function based on the total pressure. The thermodynamic consistency of the VLE data of the ternary system was tested with the method of McDermott−Ellis, modified by Wisniak and Tamir. Also, the ternary system data were compared with the predicted values, using the parameters of Wilson model obtained from the binary systems. The predicted bubble-point temperature and the vapor composition for the ternary system were in good agreement with the experimental results.

Measurement of (liquid + liquid) equilibria for ternary systems of ( N-formylmorpholine + benzene + cyclohexane) at temperatures (303.15, 308.15, and 313.15) K

This work demonstrates the ability of N-formylmorpholine (NFM) to act as an extraction solvent for the removal of benzene from its mixture with cyclohexane. The (liquid + liquid) equilibria (LLE) were measured for a ternary system of { N-formylmorpholine (NFM) + benzene + cyclohexane} under atmospheric pressure and at temperatures (303.15, 308.15, and 313.15) K. The experimental distribution coefficients ( K) and selectivity factors ( S) were obtained to reveal the extractive effectiveness of the solvent for separation of benzene from cyclohexane. The LLE results for the system studied indicate that increasing temperature decreases selectivity of the solvent. The reliability of the experimental results was tested by applying the Othmer–Tobias correlation. In addition, the universal quasichemical activity coefficient (UNIQUAC) and the non-random two liquids equation (NRTL) were used to correlate the LLE data using the interaction parameters determined from the experimental data. The root mean square deviations (RMSDs) obtained comparing calculated and experimental two-phase compositions are 0.0367 for the NRTL model and 0.0539 for the UNIQUAC model.

Measurement and Modeling of Liquid−Liquid Equilibrium for Ternary and Quaternary Mixtures of Water, Methanol, 2-Propanol, and 2,2,4-Trimethylpentane at 293.2 K

Liquid−liquid equilibrium (LLE) phase compositions for ternary and quaternary mixtures of water, methanol, 2-propanol, and 2,2,4-trimethylpentane were measured at 293.2 K. The universal quasichemical activity coefficient (UNIQUAC) model was used to model the experimental observations. Binary interaction parameters were estimated from the experimental equilibrium phase compositions. The agreement between calculations and experimental observations was very good with an overall root-mean-square deviation (rmsd) of 0.53 %.

Liquid−Liquid(−Liquid) Equilibria in Ternary Systems of Aliphatic Hydrocarbons (Heptane or Octane) + Phenols + Water

The liquid−liquid equilibria (LLE) and liquid−liquid−liquid equilibria (LLLE) in eight ternary systems were determined by photometric turbidity titration at atmospheric pressure. Additionally, the compositions of coexisting phases were determined with analytic methods. The measurements in the systems heptane or octane + phenol + water were realized at temperatures of (313.15 and 333.15) K. The equilibrium data in the systems heptane + 2-cresol or 3-cresol or 4-cresol + water and octane + 2-cresol or 3-cresol or 4-cresol + water were estimated at temperatures of (298.15 and 323.15) K. The excess Gibbs energy nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) activity coefficient models as well as the Elliott−Suresh−Donohue equation of state (ESD EoS) were used to predict the LLE or LLLE in the investigated ternary systems. The binary interaction parameters were calculated using vapor−liquid and LLE data from the literature or data predicted with the modified universal quasichemical functional-group activity coefficient (UNIFAC Dortmund) model.

P, ρ, T Measurements and Isobaric Vapor−Liquid−Equilibria of the 1,3,3-Trimethyl-2-oxabicycle[2,2,2]octane + Propan-1-ol Mixture: Cubic and Statistical Associating Fluid Theory-Based Equation of State Analysis

Densities measured at pressures from (20 to 40) MPa and the temperatures (283.15, 298.15, 313.15, and 328.15) K and isobaric (vapor + liquid) equilibrium (VLE) at pressures of (33.33, 66.66, and 101.33) kPa are reported for the mixture {1,8-cineole(1,3,3-trimethyl-2-oxabicycle[2,2,2]octane) + propan-1-ol} in the whole composition range. Excess molar volumes, isobaric thermal expansions, and isothermal compressibilities were calculated from the density data. VLE data were correlated by means of three activity coefficient models [Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC)], and their thermodynamic consistency was determined. Four equations of state (EOS), namely, the Peng−Robinson, the Patel−Teja, statistical associating fluid theory (SAFT), and perturbed-chain statistical associating fluid theory (PC-SAFT), were used first to predict (interaction parameters, kij, equal to zero) both the density and the VLE behavior of the system and second to correlate the VLE by adjustment of the interaction parameters for each EOS.

Liquid−Liquid Equilibrium of (Water + Pentane-2,4-dione + Ethyl Ethanoate) and (Water + Pentane-2,4-dione + Cyclohexane) at (298.15 and 313.15) K

Liquid−liquid equilibrium (LLE) data of the solubility curves for ternary systems of water + pentane-2,4-dione + ethyl ethanoate and tie-line compositions for both of the ternary systems of water + pentane-2,4-dione + ethyl ethanoate and water + pentane-2,4-dione + cyclohexane were determined at (298.15 and 313.15) K and at a pressure of 101.3 kPa. Distribution coefficients were evaluated for the immiscible region. The reliability of the experimental tie-lines has been confirmed by using the Othmer−Tobias correlation. The experimental data were fitted using the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) equations; parameters of these two models were regressed.

Experimental Measurements and Correlations of Liquid−Liquid Equilibria for the Ternary and Quaternary Mixtures Formed by Dialkyl Carbonates at T = 298.15 K

Tie-line data for two quaternary systems of (water + 1-butanol + diethyl carbonate (DEC) + dimethyl carbonate (DMC)) and (water + 1-butanol + hexane + DMC) and two relevant ternary systems of (water + 1-butanol + DEC) and (water + 1-butanol + DMC) at T = 298.15 K and atmospheric pressure were determined. The experimental ternary and quaternary (liquid + liquid) equilibrium results were correlated by using the modified universal quasichemical activity coefficient (UNIQUAC) model, and the interaction parameters were obtained. The root-mean-square deviations of the two quaternary systems correlations were 0.56 % and 0.75 %, respectively. Distribution coefficients were calculated to evaluate the solubility of DMC in two phases.