Equilibria In Ternary Systems Research Articles

Analysis of Vapor–Liquid Equilibrium in Ternary Systems for an Adequate Planning of Their Experimental Determination and Correlation

Analysis of Vapor–Liquid Equilibrium in Ternary Systems for an Adequate Planning of Their Experimental Determination and Correlation

Thermodynamic Modeling of Liquid-Liquid Equilibrium in Ternary Systems with Biodiesel and Isolated Ester (Methyl Palmitate)

Liquid-liquid equilibrium data were measured and analyzed for two ternary systems (biodiesel + methanol + glycerol and methyl palmitate + methanol + glycerol). Biodiesel, produced by the conventional chemical route at 60 °C for 60 min, using methanol and soybean oil at a molar rate of 10:1 and potassium hydroxide concentration (KOH) of 1 wt% exhibited thermal decomposition at temperatures between 100 and 250 ºC, reaching mass loss of approximately 98.8%, confirming soybean oil conversion into biodiesel by gas chromatography and thermogravimetry. Tie line composition quality was verified using Othmer-Tobias and Hand correlation equations. The distribution and selectivity coefficients were calculated for the immiscibility regions. The experimental tie line data exhibited good correlation in the UNIQUAC and NRTL thermodynamic models. The biodiesel system displayed deviations of 0.66 and 0.53% for the UNIQUAC and NRTL models, respectively. In addition, the methyl palmitate system showed a 1.23 and 0.48% deviation for the UNIQUAC and NRTL model, respectively. The individual behavior of the main biodiesel esters , based on the UNIQUAC model parameters, demonstrated that the type of fatty acid does not interfere in model correlation, likely due to the similarity between their composition and properties.

Estimation of Thermodynamic Properties and Phase Equilibria in Systems of Deep Eutectic Solvents by PC-SAFT EoS

This study examines the capabilities and shortcomings of perturbed-chain-statistical associating fluid theory equations of state (PC-SAFT EoS) applied for predicting properties and phase equilibria in systems of deep eutectic solvents. Treating deep eutectic solvents as pseudo-pure compounds and describing them as mixtures of two independent constituents are explored. Examples of choline chloride as the hydrogen bond acceptor (HBA) and levulinic acid, ethylene glycol, and phenol as hydrogen bond donors (HBDs) in a 1:2 molar ratio are considered. Excess properties of deep eutectic solvents with n-alkanols and water along with solubilities of carbon dioxide and ammonia are also considered. Besides that, liquid–liquid ternary systems of deep eutectic solvents with n-alkanes and 1-alkanols are analyzed. It has been found that although the pseudo-pure compounds approach with 2B associative scheme correctly estimates excess volumes, it exhibits poor accuracy in predicting excess enthalpies, solubility data, and liquid–liquid equilibria in ternary systems. When a temperature-dependent binary interaction between HBA and HBDs is applied, the individual approach predicts these properties in a more accurate manner.

Experimental Data of Fluid Phase Equilibria- Correlation and Prediction Models: A Review

The examples of phase equilibria in binary systems, solid/liquid (SLE), liquid/liquid (LLE), vapor/liquid (VLE), as well as liquid/liquid equilibria in ternary systems mainly containing ionic liquids (ILs), or the infragrance materials, or pharmaceuticals with molecular organic solvents, such as an alcohol, or water, or hydrocarbons, are presented. The most popular correlation methods of the experimental phase equilibrium data are presented, related to the excess Gibbs free energy models such as Wilson, universal-quasichemical, UNIQUAC and non-random two-liquid model, NRTL as well as several popular theories for the modeling of the phase equilibria and excess molar enthalpy, HE in binary or ternary mixtures are presented: the group contribution method (Mod. UNIFAC) and modified UNIFAC model for pharmaceuticals and lattice theory based on non-random hydrogen bonding (NRHB). The SLE, LLE, or VLE and HE of these systems may be described by the Perturbed-Chain Polar Statistical Associating Fluid Theory (PC-SAFT), or a Conductor-like Screening Model for Real Solvents (COSMO-RS). The examples of the application of ILs as extractants for the separation of aromatic hydrocarbons from alkanes, sulfur compounds from alkanes, alkenes from alkanes, ethylbenzene from styrene, butan-1-ol from water phase, or 2-phenylethanol (PEA) from water are discussed on the basis of previously published data. The first information about the selectivity of extrahent for separation can be obtained from the measurements of the limiting activity coefficient measurements by the gas–liquid chromatography technique. This review outlines the main research work carried out over the last few years on direct measurements of phase equilibria, or HE and limiting activity coefficients, the possibility of thermodynamic modeling with emphasis on recent research achievements and potential for future research.

Investigation of the Phase Equilibrium in Ternary Systems Formed by 2,2,2-Trifluoroethanol, Water, and Organic Alcohols

The phase equilibrium in binary constituents of ternary systems formed by 2,2,2-trifluoroethanol, water, and an organic alcohol (methanol, ethanol, or isopropanol) was experimentally investigated. It was shown that the methanol–2,2,2-trifluoroethanol, 2,2,2-trifluoroethanol–ethanol, and 2,2,2-trifluoroethanol–isopropanol systems at atmospheric pressure are characterized by the presence of binary maximum-boiling azeotropes. The phase equilibrium in the 2,2,2-trifluoroethanol–methanol–water, 2,2,2-trifluoroethanol–ethanol–water, and 2,2,2-trifluoroethanol–isopropanol–water ternary systems was calculated by mathematical modeling using Aspen Plus® V. 9.0 software.

Understanding and Prediction of the Clouding Phenomenon by Spontaneous and Effective Packing Concepts

AbstractIn this work, we show by which mechanism branching of the hydrocarbon chains influences the cloud point of nonionic, ethoxylated surfactants. The temperature‐induced separation into a dilute and a concentrated liquid phase is of liquid–gas type and can be explained by the relative probability of endcaps and branching points of the cylindrical micelles in both phases. The influence of branches on the hydrocarbon chains can be easily understood by means of spontaneous and effective packing concepts, while quantification via hydrophilic/lipophilic balance (HLB), hydrophilic‐lipophilic difference (HLD), and HLD‐Net Average Curvature requires parametrization. The phase equilibrium above the cloud point phenomenon is equivalent to the Winsor I type phase equilibrium, one of the five known phase equilibria in ternary systems.

Liquid–Vapor Phase Equilibria in Ternary Systems Formed by n-Alcohols and n-Alkyl Ethanoates

The boiling points of solutions of ternary systems formed by ethanol, n-propanol, n-butanol, and esters of ethanoic acid are measured via ebulliometry at different pressures. Coefficients of the activity of the solutions’ components are calculated using Wilson equations and the NRTL. The calculation results are verified experimentally.

Liquid–Liquid Equilibria for Ternary Systems of (Ethyl Methyl Carbonate + Methanol or Ethanol + Water) at 293.15, 303.15, and 308.15 K

Liquid-phase composition values for {water + methanol + ethyl methyl carbonate (EMC)} and (water + ethanol + EMC) were determined at temperatures of 293.15, 303.15, and 308.15 K at 101 kPa. Thermod...

Extensive Evaluation of the Conductor-like Screening Model for Real Solvents Method in Predicting Liquid-Liquid Equilibria in Ternary Systems of Ionic Liquids with Molecular Compounds.

A conductor-like screening model for real solvents (COSMO-RS) is nowadays one of the most popular and commonly applied tools for the estimation of thermodynamic properties of complex fluids. The goal of this work is to provide a comprehensive review and analysis of the performance of this approach in calculating liquid-liquid equilibrium (LLE) phase diagrams in ternary systems composed of ionic liquid and two molecular compounds belonging to diverse families of chemicals (alkanes, aromatics, S/N-compounds, alcohols, ketones, ethers, carboxylic acid, esters, and water). The predictions are presented for extensive experimental database, including 930 LLE data sets and more than 9000 data points (LLE tie lines) reported for 779 unique ternary mixtures. An impact of the type of molecular binary subsystem on the accuracy of predictions is demonstrated and discussed on the basis of representative examples. The model's capability of capturing qualitative trends in the LLE distribution ratio and selectivity is also checked for a number of structural effects. Comparative analysis of two levels of quantum chemical theory (BP-TZVP-COSMO vs BP-TZVPD-FINE) for the input molecular data for COSMO-RS is presented. Finally, some general recommendations for the applicability of the model are indicated based on the analysis of the global performance as well as on the results obtained for systems relevant from the point of view of important separation problems.

Computation and analysis of surfaces and lines of three-phase equilibrium in ternary systems: Application illustrated for a CO2(1)+H2O(2)+2-propanol(3)-like system

In this work the rich phenomenology of the ternary three-phase equilibrium is studied for a CO2(1)+H2O(2)+2-propanol(3)-like system which presents a highly complex behavior. This is done through computations carried out over wide ranges of conditions using a model of the equation of state type. The developed computation and analysis strategies are applicable to any ternary system as described by any equation of state model, chosen for representing real systems having a high degree of complexity in their phase behavior. A systematic identification of phase equilibrium objects (or points) from which ternary three-phase lines (T-3PLs) originate is performed. Such points are used to start the computation of a variety of T-3PLs. Several computed T-3PLs are used to visualize a number of ternary three-phase surfaces (T-3PSs). Besides, the boundaries of the T-3PSs are established. A strategy to start the calculation of a T-3PL is proposed for each type of originating point. In addition, with the aim of avoiding convergence problems, a numerical continuation method is used to calculate complete T-3PLs. The visualization of 3D projections of T-3PSs in the temperature-pressure-fugacity space is proposed. This way of looking at the T-3PSs is of much help in the understanding on how they behave and interrelate. The results suggest, among other interesting conclusions, the possibility of continuous transitions from T-3PSs of a given type to T-3PSs of a different type.

Extraction of 2-Phenylethanol (PEA) from Aqueous Solution Using Ionic Liquids: Synthesis, Phase Equilibrium Investigation, Selectivity in Separation, and Thermodynamic Models.

This study assessed the effect of ionic liquids (ILs) on extraction of 2-phenylethanol (PEA) from aqueous phase. It consists the synthesis of four new ILs, their physicochemical properties, and experimental solubility measurements in water as well as liquid-liquid phase equilibrium in ternary systems. ILs are an important new media for imaging and sensing applications because of their solvation property, thermal stability, and negligible vapor pressure. However, complex procedures and nonmiscibility with water are often required in PEA extraction. Herein, a facile and general strategy using four ILs as extraction media including the synthesis of new bis(fluorosulfonyl)imide-based ILs, 1-hexyl-methylmorpholinium bis(fluorosulfonyl)imide, [HMMOR][FSI], N-octylisoquinolinium bis(fluorosulfonyl)imide, [OiQuin][FSI], 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, [BMPYR][FSI], and N-triethyl-N-octylammonium bis(fluorosulfonyl)imide, [N2228][FSI], were investigated. The thermal properties, density, viscosity, and surface tension of new ILs were measured. Calorimetric measurements (DSC) were used to determine the melting point and the enthalpy of melting as well as the glass transition temperature and heat capacity at glass transition of the ILs. The phase equilibrium in binary systems (IL + PEA, or water) and in ternary systems {IL (1) + PEA (2) + water (3)} at temperature T = 308.15 K and ambient pressure are reported. All systems present liquid-liquid equilibrium with the upper critical solution temperature (UCST). All ILs revealed complete miscibility with PEA. In all ternary systems immiscibility gap was observed, which classified measured systems as Treybal's type II. The two partially miscible binaries (IL + water) and (PEA + water) exist in these systems. The discussion contains the specific selectivity and the solute distribution ratio of separation for the used ILs. The commonly used NRTL model was used for the correlation of the experimental binary and ternary systems with acceptable root-mean-square deviation. The prediction of binary and ternary compositions was provided with acceptable deviations using COSMO RS. The data of ternary LLE show the possible use of [HMMOR][FSI] as a good entrainer for the separation of PEA from water using solvent extraction.

Measurement and prediction of liquid-liquid equilibria in ternary systems containing water, an organic component, and cyclohexanol

The liquid-liquid equilibria of the four ternary mixtures water + heptane + cyclohexanol, water + toluene + cyclohexanol, water + cyclohexane + cyclohexanol, and water + cyclohexylamine + cyclohexanol were measured at 298.15 K and 323.15 K at atmospheric pressure. The binodal curves were determined by photometric turbidity titration.Our experimental data are compared with the prediction results from both UNIQUAC and NRTL activity coefficient models and the equation of state proposed by Elliott, Suresh, and Donohue (ESD EOS). For this purpose, interaction parameters were determined using binary phase equilibrium data. Due to the sparse amount of binary equilibrium data in literature, the vapour-liquid equilibrium in the binary toluene + cyclohexanol system was determined at 333.15 K and 363.15 K at reduced pressure. When predicting the experimental LLE behaviour of the considered systems, ESD EOS seems to be superior to the UNIQUAC and NRTL approach.

Phase equilibrium investigation with ionic liquids and selectivity in separation of 2-phenylethanol from water

This work presents some important issues and topics related to possible extraction of 2-phenylethanol (PEA) from aqueous phase “in situ” during the biosynthesis with ionic liquids (ILs). It consists of a series of experimental phase equilibrium measurements in binary and ternary systems. Three ILs as extraction media are proposed for the extraction process based on phase equilibria in ternary systems {IL (1)+PEA (2)+water (3)} at temperature T=308.15K and ambient pressure. The systems are composed of the following ILs: 1-hexyl-1-methylmorpholinium bis{(trifluoromethyl)sulfonyl}imide, [HMMOR][NTf2], 1-allyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [AMIM][NTf2], and diethylmethylsulfonium bis{(trifluoromethyl)sulfonyl}imide, [S221][NTf2]. A differential scanning calorimetry (DSC) was used to determine the thermal properties of the ILs. The synthesis of new [HMMOR][NTf2] IL and its thermal and physicochemical properties as density, viscosity, surface tension were presented. The volume expansivity, as well as the surface thermodynamic functions, such as surface entropy and enthalpy have been derived from the temperature dependence of the surface tension values, as well as the critical temperature, parachor and speed of sound for all ILs were presented. The correlation of the liquidus curves in binary systems and tie-lines in ternary systems was undertaken with the NRTL equation. These results of solubility can be used to design future alternative technological processes of the extraction of PEA from fermentation broth.

Measurement and calculation of solid–liquid equilibrium for ternary systems of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene + ethanol/n-propanol

The stable (solid+liquid) phase equilibrium in ternary systems of 3,4-dichloronitrobenzene+2,3-dichloronitrobenzene+ethanol and 3,4-dichloronitrobenzene+2,3-dichloronitrobenzene+n-propanol at three temperatures was determined by means of an isothermal solution saturation method under pressure p=101.2kPa. The isothermal phase diagrams of the two ternary systems were plotted on the basis of the experimental mutual solubility data. The equilibrium solids formed in the two systems were identified by Schreinemakers’ method of wet residues. It was found that each phase diagram included one co-saturated point, two co-saturated curves and three crystallization zones in the ternary systems of 3,4-dichloronitrobenzene+2,3-dichloronitrobenzene+ethanol and 3,4-dichloronitrobenzene+2,3-dichloronitrobenzene+n-propanol. Two pure solid phases were formed in the studied systems, which were pure 2,3-dichloronitrobenzene and pure 3,4-dichloronitrobenzene. The crystallization zone of 3,4-dichloronitrobenzene was smaller than that of 2,3-dichloronitrobenzene at a given temperature, which showed that 2,3-dichloronitrobenzene could be easily separated from the solution. Furthermore, the solid–liquid phase diagrams were calculated by using NRTL model. The calculated phase diagrams agreed well with the experimental ones. Knowledge of (solid+liquid) phase equilibrium and ternary phase diagrams would be very valuable to design and optimize the solvent crystallization process of 2,3-dichloronitrobenzene and other crystallization processes involving the two ternary systems.

Experimental and Computational Study on Liquid–Liquid Equilibrium in Ternary Systems of γ-Valerolactone, Toluene, and Hydrocarbons

γ-Valerolactone is a biomass-derived compound widely applicable in chemical industry, especially as a solvent, additive to fuels, or precursor for other chemicals. In contrast with the industrial importance of γ-valerolactone, there is an insufficient number of mixture phase-equilibria in the literature. Therefore, the aim of this work was to measure liquid–liquid equilibrium data for ternary systems γ-valerolactone + toluene + hydrocarbon (hydrocarbons were n-heptane, n-decane, n-dodecane, and cyclohexane) by the direct analytical method at 298.15 K and 0.1 MPa. The obtained experimental data were processed and correlated by the nonrandom two-liquid (NRTL) model. The NRTL binary parameters between γ-valerolactone and toluene were evaluated from the measured ternary liquid–liquid equilibrium data, whereas the other binary parameters were obtained by regression of binary liquid–liquid equilibrium data or vapor–liquid equilibrium and excess enthalpy data taken from literature. The predictive performance of ...

Protolytic and coordination equilibria in aqueous solutions of nickel(II) complexonates

Protolytic and coordination equilibria in ternary systems containing a nickel(II) salt, ethylenediaminetetraacetic acid, and monoamine complexones, such as iminodiacetic, hydroxyethyliminodiacetic, and nitrilotriacetic acids, were studied by absorption spectroscopy against the background of NaClO4 at I = 0.1 and T = (20 ± 2)°C. Experimental data were processed by mathematical models that were able of evaluating the possibility of existence of a wide spectrum of species in solution and to select the species sufficient for the experimental data to be reproduced from them. The compositions of polynuclear heteroligand complexonates were determined, the pH regions of their existence were established, and the equilibrium constants of reactions and the stability constants of the complexes were calculated.

Solution Equilibria of Ternary Systems Involving Nickel(II) Ion, Picolinic Acid, and the Amino Acids Histidine, Cysteine, Aspartic and Glutamic Acids

Solution equilibria of the ternary systems Ni(II)–picolinic acid (Hpic) and the amino acids aspartic acid (H2asp), glutamic acid (H2glu), cysteine (H2cys) and histidine (Hhis), where the amino acids are denoted as HiL, have been studied pH-metrically. The formation constants of the resulting mixed ligand complexes have been determined at 25 °C using a ionic strength 1.0 mol·dm−3 NaCl. In the Ni(II)–Hpic–H2asp and Ni(II)–Hpic–H2glu systems, the complexes [Ni(pic)H2L]+, Ni(pic)HL, [Ni(pic)L]− and [Ni(pic)L(OH)]2− were detected. In the Ni(II)–Hpic–H2cys system the complexes [Ni(pic)H2L]+ and [Ni(pic)L]− are present. Additionally, in the Ni(II)–Hpic–Hhis system the species [Ni(Hpic)HL]2+, Ni(pic)L and [Ni(pic)L(OH)]− were identified. The species distribution diagrams as functions of pH are briefly discussed.

Geometrical study of the three-dimensional temperature–composition diagrams. An important aid to understand the behavior of the liquid–vapour equilibrium in ternary systems

In this work the usefulness of qualitatively studying and drawing three-dimensional temperature–composition diagrams for ternary systems is pointed out to understand and interpret the particular behavior of the liquid–vapour equilibrium of non-ideal ternary systems. Several examples have been used in order to highlight the interest and the possibilities of this tool, which should be an interesting support not only for lecturers, but also for researchers interested in experimental equilibrium data determination.

Гетеролигандные координационные соединения никеля(II) c 1,3-дикарбоксипропан-1- иминодиуксусной кислотой и дикарбоновыми кислотами в водных растворах

Equilibria in ternary systems containing cobalt (II) salt, dicarboxypropaneiminodiethanoic acid and dicarboxylic acids: oxalic, malonic and succinic were studied by spectrophotometry with Na2SO4 as a supporting electrolyte (I = 0.1) at Т = 20 ± 2 oС. The molar and proton compositions of the heteroleptic complexes and the pH ranges of their existence were determined. The stability constants of these complexes were calculated. The shares of accumulation of the complexes, which are subject to the acidity of a medium, were found. The experimental data were processed in terms of mathematical models allowing to predict the existence of a wide spectrum of complex species in solution and to ignore the species that are negligible for accurate reproduction of the observed pattern.

A Novel Method for Assessing the Effect of Pressure on Vapor–Liquid Equilibrium in Ternary Systems

In distillative separations, operating pressure is an important parameter influencing not only the cost of a given separation, but potentially its feasibility too. A reliable technique for assessing the effect of pressure on vapor–liquid equilibrium is thus imperative for robust distillation design. This paper presents a method that is not only reliable, but also allows a designer to creatively synthesize a column by finding areas where the phase equilibrium may be beneficial for a particular separation. By viewing global residue curve maps which incorporate theoretical negative compositions, pressure effects are easily traceable. It is shown how the NRTL model in particular is a very useful thermodynamic model for this unique assessment of pressure effects. Using this technique, significant insights are gained into the appearance and disappearance of azeotropes at certain pressures. Moreover, this paper presents a novel eigenvalue method which allows one to determine exact critical pressures where residu...