Universal Quasichemical Activity Coefficient Models Research Articles

Isothermal Vapour-Liquid Equilibrium Measurements for the butan-1-ol + butane-1,4-diol/butane-2,3-diol system within 353.2–388.2 K

In this study, the isothermal binary vapour-liquid equilibrium (VLE) data for the butan-1-ol + butane-1,4-diol/butane-2,3-diol system was measured and modelled, for use in the design and rating of separation processes. P-T-x-y equilibrium measurements were performed at four temperatures from approximately 353–388 K. A dynamic-analytical apparatus was utilized to perform the measurements at sub-atmospheric conditions. The measured data was modelled by employing the γ-Φ approach. The liquid-phase correction was accounted for using the Non-Random Two-Liquid and Universal Quasi-Chemical activity coefficient models while the Hayden and O'Connell correlation for the virial equation of state was used to account for the vapour-phase correction. Thermodynamic consistency tests were performed using the point and area tests for the measured experimental data and the data sets passed both tests.

Isobaric Vapor–Liquid Equilibrium Measurements and Modeling of Water + Monoethylene Glycol + NaCl Mixtures

Vapor−liquid equilibrium (VLE) data for aqueous systems in the presence of electrolytes have many industrial applications. VLE data for water + monoethylene glycol (MEG) mixtures in the presence of sodium chloride at low pressures are important to describe the effects of composition, temperature, and pressure on a MEG (gas hydrate inhibitor) regeneration unit. A modified version of the Othmer ebulliometer was applied to measure reliable VLE data for water + MEG + NaCl at 101.325, 65, and 35 kPa. Binary systems (water + MEG and MEG + NaCl) were also experimentally studied. Vapor pressures for water and MEG were determined and compared with the selected literature data via Antoine correlation. The electrolyte nonrandom two-liquid and universal quasi-chemical activity coefficient models were successfully parameterized to describe the VLE behavior for water + MEG + NaCl systems. Thermodynamic consistence of the data sets was also checked. Interaction parameter estimation followed a systematic strategy: (1) water−MEG, (2) water−NaCl, and finally (3) MEG−NaCl with the experimental data of MEG + NaCl and ternary data. MEG + NaCl solutions presented an inverted colligative property, that is, the addition of salt decreases the boiling point. VLE data indicated that water separation is less efficient due to the addition of salt. The parameterized models allow an evaluation of the MEG regeneration process as a function of temperature, pressure, and composition

Vapor–liquid equilibrium at 94 kPa and surface tension at 298.15 K for hexane + ethanol + cyclopentyl methyl ether mixture

Vapor-liquid equilibrium (VLE) and surface tension (ST) for the hexane + ethanol + cyclopentyl methyl ether mixture have been measured and modeled. VLE determinations are carried out in a dynamic Guillespie type cell at the isobaric condition of 94 kPa, whereas the dependence of ST on concentration is measured in a maximum differential bubble pressure tensiometer at atmospheric pressure and 298.15 K.The thermodynamical consistent VLE data exhibit positive deviation from ideal behavior without ternary azeotropy and are well correlated by Redlich–Kister expansion and predicted by the binary nonrandom two-liquid, Wilson and universal quasichemical activity coefficient models. The ST data exhibit negative deviation from the linear behavior and are smoothed using the Myers-Scott expansion, showing no ternary aneotropic behavior.The experimental data of VLE and ST are accurately characterized by applying the square gradient theory to the Peng–Robinson Stryjek–Vera equation of state (EoS) appropriately extended to mixtures employing the modified Huron–Vidal mixing rule. This theoretical framework shows that experimental VLE and ST data can be fully predicted by only using binary contributions within a global average absolute deviation of 1.25% for VLE and 6.1% for ST. The theoretical approach also provides a route to explore the concentration distribution of species in the interfacial region, where it is possible to conclude that hexane exhibits both adsorption and desorption; ethanol displays strong positive adsorption whereas CPME does not exhibit surface activity.

Liquid–Liquid Equilibrium for the Ternary Systems Water + 1-Butanol + 1-Hexanol or 1-Octanol at 303.15, 313.15, and 323.15 K

Liquid–liquid equilibrium data (LLE) of ternary systems {water + 1-butanol + 1-hexanol} and {water + 1-butanol + 1-octanol} were investigated at 303.15, 313.15, and 323.15 K at 101.3 kPa. The distribution coefficient (D) and selectivity factor (S) were calculated from experimental LLE data. Meanwhile, the effect of temperature on the two-phase zone of the two systems was discussed. The nonrandom two liquid and universal quasi-chemical activity coefficient models were used to regress experimental data sets and generate the relevant binary interaction parameters. Both thermodynamic models provided similar good descriptions for the studied systems with root mean square deviations between the calculated and experimental values less than 0.3%.

Experimental study of the LL, VL and VLL equilibria of water + 1-butanol + 2-octanol at 101.3 kPa

Equilibrium data for the water + 1-butanol + 2-octanol system is determined in this work. Liquid-liquid equilibrium (LLE) data are obtained at 303.15 K and 313.15 K, with a view to investigating the influence of temperature.Vapour-liquid-liquid equilibrium (VLLE) and vapour-liquid equilibrium (VLE) data of the same system are also determined at 101.3 kPa, by means of a modified Fisher Labodest recirculating still that is coupled to an ultrasonic probe. Additionally, the heterogeneous binary azeotrope of the pair water + 2-octanol is determined.Correlation parameters are obtained from the experimental results for use in the universal quasichemical (UNIQUAC) and non-random two-liquid (NRTL) thermodynamic models in CHEMCAD 7. The UNIQUAC, NRTL and original universal functional group activity coefficient (UNIFAC) models are then, in turn, used to predict the LLE and VLLE data from these correlation parameters.

Liquid–Liquid Equilibria Determination and Prediction for Ternary Systems of Water + 1,6-Hexanediamine + (1-Butanol or 1-Pentanol) at 298.2, 308.2, and 318.2 K

Data of liquid–liquid equilibria (LLE) for water + 1,6-hexanediamine + 1-butanol and water + 1,6-hexanediamine + 1-pentanol ternary systems were determined at T = 298.2, 308.2, and 318.2 K under atmospheric pressure. The distribution coefficients and selectivity factors calculated from LLE data were applied to evaluate the feasibility and effectiveness of extracting 1,6-hexanediamine from the aqueous solution. The results showed that the selectivity factors decrease with the amount of 1,6-hexanediamine increasing in the aqueous phase, and the effect of temperature is insignificant in this study. The nonrandom two-liquid and universal quasichemical activity coefficient models were also applied to regress the experimental equilibrium data of the two ternary systems and the root mean square deviation values between the correlated and experimental results were lower than 0.7%. It turned out that these phase equilibrium behaviors can be described by the two models. Meanwhile, the binary model parameters were a...

Measurement and Correlation of Ternary (Liquid + Liquid) Equilibria for Separation of Cyclohexanone from Water via Isophorone or Mesityl Oxide

Liquid–liquid equilibria provide basic data and guidance regarding the design, simulation, and development of an appropriate solvent extraction process. In the current work, the data for the liquid–liquid equilibrium (LLE) of water + cyclohexanone + isophorone and water + cyclohexanone + mesityl oxide systems have been measured at temperatures of 308.15–328.15 K and pressure of 101.3 kPa. The empirical Bachman and Hand equations were utilized to confirm the consistency of experimentally determined LLE data. Meanwhile, the solute distribution ratio and separation parameter were obtained from the experimental equilibrium data to evaluate the extraction properties of the selected solvents. Additionally, a mathematical regression of experimental tie-line compositions for all of the investigated ternary mixtures was performed by means of the nonrandom two-liquid and universal quasi-chemical activity coefficient models to acquire corresponding optimized binary interaction parameters. The correlation results were verified to be coincident with the experimental ones and revealed that the above two thermodynamic models were of high-accuracy and suitable to regress the tie-line compositions for the investigated ternary systems.

Measurement and Correlation of Isobaric Vapor–Liquid Equilibrium of Three Binary Systems Containing Chlorobenzene at 50.00 and 101.33 kPa

Isobaric vapor–liquid equilibrium (VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a modified Rose–Williams still. Gas chromatography was used to analyze the compositions of the samples and no azeotropic behavior was found. All of the measured VLE values were checked by the semi-empirical method proposed by Herington and the point-to-point Van Ness test method modified by Fredenslund. The experimental data were correlated by using the Wilson, the non-random two-liquid and universal quasi-chemical activity coefficient models. The corresponding parameters for the three models were obtained.

Measurement and Correlation of Phase Equilibria for Isobutyl Acetate + {Ethanol or Methanol} + Water at 303.15 and 323.15 K

The phase equilibrium data for the ternary systems isobutyl acetate + {ethanol or methanol} + water were determined at temperatures of 303.15 and 323.15 K, and pressure of 101.3 kPa. Both Hand and Bachman methods were used to evaluate the validity of the experimental data in the present work. In addition, the nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) models were applied to fit the experimental tie-line data, and the binary interaction parameters of the thermodynamic models were fitted. The root-mean-square devation values obtained for the NRTL and UNIQUAC activity coefficient models are less than 0.0081, which indicates that the correlated results agree with the experimental data. Moreover, the distribution coefficients and selectivities were determined and discussed.

Liquid–Liquid Equilibria for Ternary Systems of Water + Methoxycyclopentane + Alcohol (Methanol, Ethanol, 1-Propanol, or 2-Propanol)

Liquid–liquid equilibria data were determined for four ternary systems of water + alcohol + methoxycyclopentane (CPME); the alcohols used were methanol, ethanol, 1-propanol, and 2-propanol. All measurements were performed at 298.15 K and atmospheric pressure. Binodal curves were experimentally determined using both the cloud-point method and tie lines. The reliability of the tie-line data were verified by the Hand and Othmer–Tobias plots. Distribution coefficients and separation factors were determined from the tie-line data. The universal quasichemical activity coefficient model was used to correlate the experimental data. Additionally, these water–alcohol–CPME systems were compared to the water–methanol–chloroform system as a green alternative for Bligh and Dyer lipid extraction.

Liquid–liquid equilibria for ternary systems water + acetic acid + 1,2,4-trimethylbenzene and water + acetic acid + 1,3,5-trimethylbenzene at (303.2–343.2) K

Liquid–liquid equilibria (LLE) data for the ternary systems of water + acetic acid + 1,2,4-trimethylbenzene and water + acetic acid + 1,3,5-trimethylbenzene were measured under atmospheric pressure at (303.2–343.3) K. The reliability of the experimentally determined tie-line data was verified by comparison with the literature data. Both the nonrandom two-liquid (NRTL) and the universal quasi-chemical activity coefficient (UNIQUAC) models were adopted to correlate the experimental LLE data, and the binary model interaction parameters were obtained. The RMSD values as low as 0.89% and 0.51% were obtained for the two models, respectively, which shows that the experimental LLE data have been successfully correlated by both the NRTL and the UNIQUAC models. The relevant model parameters could be useful for the simulation and optimization of the related separation process. Moreover, the distribution coefficient and separation factor of acetic acid in the two ternary systems were calculated and discussed in detail.

A new insight to validation of local composition models in binary mixtures using molecular dynamic simulation

A computational method based on molecular dynamics (MD) simulation is developed to predict the interaction parameters in local composition (LC) models such as Wilson, nonrandom two‐liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC) applicable in vapor‐liquid equilibrium calculations so that LC models are validated. The five binary mixtures of water‐acetonitrile, water‐isopropanol, methanol‐chloroform, acetone‐cyclohexane, and meta xylene‐benzene were simulated. The MD simulations are performed using the condensed phase optimized molecular potential for atomistic simulation studies force field and all ranges of radial distribution function (RDF) are considered. In addition, the interaction parameters are determined by optimization through experimental data and are compared with the MD results. The interaction parameters are calculated through RDF where the effective radius is investigated by experimental data. The present results demonstrate that interaction parameters are composition dependent which are best fitted by a third‐order polynomial relation. Based on the deviation in the activity coefficients, the results of the UNIQUAC model are more accurate than Wilson and NRTL models. © 2015 American Institute of Chemical Engineers AIChE J, 62: 275–286, 2016

Liquid–Liquid Equilibria for the Methyl Tert-Butyl Ketone + Phenol + Water Ternary System at 298.15, 313.15 and 323.15 K

In this work, liquid–liquid equilibria data for the methyl tert-butyl ketone (MTBK) + phenol + water ternary system at 298.15, 313.15 and 323.15 K, under atmospheric pressure, were measured. The experimental tie-line data’s reliability was verified by the Hand and Bachman equations. The distribution coefficient, together with the selectivity, was used to assess the extraction performance of MTBK. The experimental data were correlated with the nonrandom two-liquid and universal quasi-chemical activity coefficient models to yield binary interaction parameters for relevant process simulations.

Liquid–Liquid Equilibrium for Ternary Systems Water + Acetic Acid + m-Xylene and Water + Acetic Acid + o-Xylene at (303.2 to 343.2) K

Liquid–liquid equilibrium (LLE) for ternary systems water + acetic acid + m-xylene and water + acetic acid + o-xylene were measured at (303.2 to 343.2) K and under atmospheric pressure. The consistency of the experimental tie-line data was checked by both the Othmer–Tobias and the Hand equations as well as verified by comparison with the literature data. Both the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were adopted to correlate the measured LLE data, and the binary interaction parameters were obtained by data-fitting. The predicted LLE data by using the obtained model parameters show good consistency with the literature data. It indicates the obtained binary NRTL and UNIQUAC model interaction parameters could be used in the calculation of LLE for the ternary systems water + acetic acid + m-xylene and water + acetic acid + o-xylene as well as for the design, simulation, and optimization of the related separation process.

Isothermal and Isobaric Vapor–Liquid Equilibrium and Excess Molar Enthalpy of the Binary Mixtures of 2-Methoxy-2-methylpropane + 2-Methyl-2-butanol or + 2-Butanol

Low molecular weight ethers have been used for many years as enhancers for fossil fuels combustion. A gradual replacement of mineral oils by bio-oils requires additional knowledge about the thermodynamic properties of bio-alcohol and ether mixtures. In this work, isothermal vapor–liquid equilibria (VLE) of the binary mixture of methyl tert-butyl ether (MTBE, 2-methoxy-2-methylpropane) with 2-methyl-2-butanol and MTBE with 2-butanol were measured isothermally at 323 K and at constant 90.1 kPa pressure with a recirculation still apparatus. Excess molar enthalpy (hE) was measured for two binary mixtures at 308 K, 323 K, and 363 K by using a SETARAM C80 calorimeter equipped with a flow mixing cell. A comprehensive consistency analysis was performed for the obtained data, and the experimental data were correlated with the nonrandom two liquid and universal quasichemical activity coefficient models. The results were compared with UNIFAC-Dortmund and COSMO-RS predictive models. The investigated mixtures are clos...

Liquid–Liquid Equilibria for Ternary Systems: Methyl Butyl Ketone + Phenol + Water and Methyl Butyl Ketone + Hydroquinone + Water at 298.15 K and 323.15 K

Liquid–liquid equilibria (LLE) data for two ternary systems: methyl butyl ketone (MBK) + phenol + water and methyl butyl ketone + hydroquinone + water have been measured at 298.15 K and 323.15 K under atmospheric pressure. The reliability of experimental tie-line data was checked by Hand and Bachman equations. The distribution coefficient and selectivity were used to evaluate the extraction performance of methyl butyl ketone. In addition, NRTL (nonrandom two-liquid) and UNIQUAC (universal quasi-chemical activity coefficient) models were used to correlate experimental data, which yielded corresponding binary interaction parameters. Results from both models agree with each other well. NRTL model presents a stronger predictive power than UNIQUAC model.

Isobaric vapor–liquid equilibrium for binary system of 2-ethylthiophene + n-octane at 101.33 kPa

Isobaric vapor–liquid equilibrium (VLE) data of 2-ethylthiophene and n-octane binary system were measured at 101.33kPa with a modified Rose-Williams still. Gas chromatography was used to analyze compositions of the samples from the vapor–liquid equilibrium system. The VLE measurement passed the thermodynamic consistency test proposed by Herington and no azeotropic behavior was found. The experimental data were correlated by Wilson, the non-random two-liquid (NRTL) and universal quasi-chemical activity coefficient (UNIQUAC) models, respectively. The corresponding parameters for the three models were obtained. Results showed that the Wilson model gave better predictions than NRTL and UNIQUAC models.

Measurements and Correlation of Liquid–Liquid Equilibria for the Ternary System Water + Cyclohexanol + Cyclohexanone

Liquid–liquid equilibrium (LLE) data of the ternary system water + cyclohexanol + cyclohexanone was measured from (303.2 to 333.2) K. The reliability of the experimental tie-line data was confirmed by applying the Othmer–Tobias and the Bachman equations. The equilibrium data were correlated with the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models. The calculated LLE data for the ternary system agreed well with the experimental data. The root-mean-square deviations (rmsd’s) obtained comparing calculated and experimental two-phase compositions are 0.46 % for the NRTL model and 0.44 % for the UNIQUAC model. The obtained interaction parameters can be used in the calculation of LLE for the ternary system water + cyclohexanol + cyclohexanone as well as for the design, simulation, and optimization of the related separation process.

Isobaric Vapor–Liquid Equilibrium Data for the System of 1-Methyl-2-Ethylbenzene + 1,2,4-Trimethylbenzene at 10 kPa

Vapor–liquid equilibrium (VLE) data of 1-methyl-2-ethylbenzene (1M2EB) + 1,2,4-trimethylbenzene (124TMB) at 10 kPa were measured by using a modified Rose–Williams type recirculation still. The thermodynamic consistency of the VLE data was examined by the Herrington and Fredenslund methods. Experimental data were correlated by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC) models. All of the models were satisfactorily correlated with the VLE data. The result showed that the UNIQUAC model was slightly more suitable to correlate the experimental data and no azeotropic behavior was observed.

Liquid–Liquid Equilibrium for the Ternary System 2-Methyl-1-propanol + 3-Methyl-1-butanol + Water at (298.15, 323.15, and 348.15) K

Liquid–liquid equilibrium (LLE) data for the ternary system 2-methyl-1-propanol + 3-methyl-1-butanol + water have been measured at (298.15, 323.15, and 348.15) K, respectively, under atmospheric pressure in this article. The Othmer–Tobias and Bachman equations were used to check the reliability of the obtained tie-line data. In addition, both NRTL (nonrandom two-liquid) and UNIQUAC (universal quasichemical) activity coefficient models were applied to the ternary system, and the relevant interaction parameters were regressed with the experimental data. The predicted values by both methods were compared with the measured experimental data. The consistency of the two models was excellent, with a better prediction by the NRTL model with a parameter α of 0.3. The obtained interaction parameters of both models can be used in the calculation of the liquid–liquid phase equilibrium of aqueous solution comprising 2-methyl-1-propanol and 3-methyl-1-butanol as well as for the design and optimization of the related se...