Two-liquid Activity Coefficient Model Research Articles

Isobaric vapor-liquid equilibrium of 2-propanone+2-butanol system at 101.325 kPa: Experimental and molecular dynamics simulation

Isobaric vapor-liquid equilibrium (VLE) data for binary mixtures of 2-propanone+2-butanol have been measured at 101.325 kPa. The measurements were in a modified recirculating type of Othmer equilibrium still. All the data passed the thermodynamics consistency test and no azeotropic behavior was exhibited. The experimental VLE data were correlated with the Wilson, non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models. The correlation results showed that the experimental data were well correlated with those models. The experimental data also showed slight deviations from the predicted results using UNIFAC and modified UNIFAC (Dortmund) models. To gain more insight into the nature of interactions between 2-propanone molecule and alcohol, we analyzed the hydrogen-bonds, the electrostatic (Coulomb) interactions, and the van der Waals (Lennard- Jones) interaction energies extracted from MD simulations. In addition, the structural property of liquid phase was characterized through radial distribution function (RDF) to establish favorable interactions between 2-propanone and 2-butanol in the mixture.

Isobaric Vapor–Liquid Equilibria for Two Binary Systems {Propylene Glycol Methyl Ether Acetate + Methanol} and {Propylene Glycol Methyl Ether Acetate + N,N-Dimethylformamide} at p = 30.0, 50.0, and 70.0 kPa

The isobaric vapor–liquid equilibria (VLE) data for two binary systems of propylene glycol methyl ether acetate (PMA) + N,N-dimethylformamide (DMF) and propylene glycol methyl ether acetate (PMA) + methanol (MeOH) at 30.0, 50.0, and 70.0 kPa were measured by utilizing a modified Rose–Williams still type apparatus which could be able to quickly form the dual cycle of continuous vapor and liquid phase in this work. On the basis of Herington area test and Van Ness point test, the thermodynamic consistency of the experiment data was verified. Meanwhile, VLE data that we obtained were correlated with nonrandom two-liquid (NRTL) and Margules activity coefficient models. The results demonstrated that the calculated values were in good conformity with the experimental data in this study. In addition, azeotropic behavior was observed in the binary system of PMA and DMF at reduced pressures.

PARAMETER INTERAKSI BINER KESETIMBANGAN UAP-CAIR CAMPURAN ALKOHOL UNTUK OPTIMASI PROSES PEMURNIAN BIOETANOL

In this work, the binary interaction parameters of vapor-liquid equilibrium for the mixtures of primary alcohols (methanol, ethanol, 1-propanol or 1-butanol) with C5 alcohols were obtained. A total of 15 systems that consisted of isobaric vapor-liquid equilibrium data at atmospheric pressure were selected. The binary interaction parameters were determined as temperature function by correlating the selected vapor-liquid equilibrium data using the Wilson, Non-Random Two-Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) activity coefficient models. The binary interaction parameters were described as the temperature-dependent to increase the capability of the parameters for the application in wide range of temperature. The correlation showed good results because the root mean square deviation (RMSD) between the calculation values and experimental data were relatively low. The obtained parameters were very useful for optimizing the distillation column in the bio-ethanol purification process.

Determination and Correlation of Liquid–Solid Phase Behaviors of Polyhydric Alcohol + KBr + H2O Ternary Systems at 288.15, 298.15, and 308.15 K

The solubility, density, and refractive index of 1,2-propanediol + KBr + H2O, ethylene glycol + KBr + H2O, and glycerin + KBr + H2O ternary systems are determined at 288.15, 298.15, and 308.15 K. In all cases, the solubility of KBr decreases with increasing concentration of polyhydric alcohol. The liquid–solid equilibrium experimental data are correlated using the nonrandom two-liquid (NRTL) activity coefficient model, considering nondissociation of the dissolved salt in the liquid phase, and new interaction parameters are estimated. The mean deviations show a good applicability of the NRTL model. Simultaneously, the corresponding unsaturated systems are investigated, and the concentration factors are discussed.

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.