Ternary Liquid-liquid Equilibrium Data Research Articles

Liquid-liquid equilibria of the ternary systems water + C1 – C3 alcohols + dimethyl adipate at 298.15 K and atmospheric pressure: Experimental data and modeling

The aim of this study was to examine the possibility of using a green organic solvent, dimethyl adipate (DMA), as a separation agent in the extraction of different alcohols from aqueous solutions. For that purpose, the liquid–liquid equilibria (LLE) of four ternary systems were analytically determined at 298.15 K and atmospheric pressure using stirred and thermo-regulated cells: {water + methanol + dimethyl adipate (DMA)}, {water + ethanol + DMA}, {water + 1-propanol + DMA}, {water + 2-propanol + DMA}. Phase diagrams for these four ternary systems were obtained by determining a binodal curve and tie-lines data using a visual cloud-point method, but also gas chromatography. Distribution coefficients and separation factors were calculated for the immiscibility region. Hand and Othmer-Tobias correlations were used to examine the reliability of the tie-line data. In addition, the experimental ternary LLE data were correlated with the UNIversal QUAsiChemical (UNIQUAC) activity coefficient models. The obtained results showed that DMA is a suitable candidate for the extraction of methanol, ethanol, 1-propanol, and 2-propanol from water. With some alcohols, this potential is more noticeable than with others. The potential of DMA as a separation agent is increasing in the following sequence: methanol < ethanol < 2-propanol < 1-propanol, and that also could be noticed from the selectivity values that also increase in this sequence. The UNIQUAC model proved as successful in correlating the LLE data.

Ternary liquid–liquid equilibria for 2-phenylethyl acetate + 2-phenylethanol + water and 2-phenylethyl acetate + acetic acid + water at atmospheric pressure

2-Phenylethyl acetate can normally be produced by the esterification of 2-phenylethanol with acetic acid via a reactive distillation process. The multiphase coexistence behavior is a component of esterification and is important for the design of the reactive distillation process. In this report, the ternary liquid–liquid equilibrium (LLE) results of 2-phenylethyl acetate + 2-phenylethanol + water and 2-phenylethyl acetate + acetic acid + water at 303.15, 323.15, and 343.15 K under atmospheric pressure are presented. The ternary LLE data regression results were obtained using NRTL and UNIQUAC models with an absolute average deviation (AAD%) value of less than 2 %. The determined binary interaction parameters were verified by the GUI-MATLAB tool. Furthermore, the results predicted by the UNIFAC model for the investigated ternary LLE systems are acceptable.

Liquid-liquid equilibrium studies on the removal of naphthalene / 2-methylnaphthalene / dibenzothiophene from model oil using ionic liquids

Liquid-liquid extraction, has been used as an alternative method, for the dearomatization and desulfurization of a model oil using ionic liquids (ILs). The most recent work employs six ILs of high selectivity to aromatic and sulfur-containing compounds in ternary liquid-liquid equilibrium (LLE) systems. The best three ILs from the LLE ternary systems were used in a model multicomponent systems. The ILs were selected as extractive solvents for the extraction of naphthalene (N), 2-methylnaphthalene (2MN) and dibenzothiophene (DBT) from 1,3-diisopropylbenzene (1,3DIPB) in the ternary LLE data. Ternary mixtures of {IL (1) + N , or 2MN, or DBT (2) + 1,3DIPB (3)} and multicomponent mixtures {IL + N + 2MN + DBT + 1,3DIPB} were investigated at temperature T = 313.15 K and pressure 101 kPa. For this reason, the imidazolium-, pyridinium- and morpholinium-based ILs were selected: 1-ethyl-3-methylimidazolium dicyanamide, [EMIM][DCA], 1-allyl-3-methylimidazolium dicyanamide, [AMIM][DCA], 1‑butyl‑3-methylimidazolium tiocyanate, [BMIM][SCN], 1‑butyl‑4-methylpyridinium dicyanamide, [B 4 MPy][DCA], N-(2-hydroxyethyl)pyridinium tricyanomethanide, [Py2OH][TCM] and (3-hydroxypropyl)-1-methylmorpholinium dicyanamide, [ N C 3 OHMMOR][DCA]. The suitability of the ILs as extractive solvents has been evaluated in terms of solute distribution ratio and selectivity. All the ILs showed high selectivity in the extraction of N, 2MN and DBT from 1,3DIPB in ternary and multicomponent systems. All LLE experimental data were correlated with the NRTL model. The highest extraction efficiency of N, 2MN and DBT in LLE data was observed for [B 4 MPy][DCA] (22.3 wt%, 36.8 wt% and 45.5 wt%, respectively). Much higher extraction efficiency was obtained in extraction of N, 2MN and DBT from the model oil stream in a single extraction stage (2IL:1 M.Str., m/m) and in two-stage extraction (2IL:1 M.Str., m/m). The extraction efficiency of N, 2MN and DBT from the model oil stream (2IL:1 M.Str., m/m) was 71.1 wt%, 80.4 wt% and 76.4 wt%, with [BMIM][SCN], or 69.3 wt%, 86.4 wt% and 82.9 wt% with [B 4 MPy][DCA], or 69.2 wt%, 69.4 wt% and 69.0 wt% with [AMIM][DCA], respectively in two-stage extraction. Graphical Abstract .

Separation of phenol from aqueous solution by 2-octanone: Phase equilibrium measurements and thermodynamic studies

The applicability of 2-octanone as solvent for the liquid phase extraction of phenol from aqueous solution was investigated in this work. The liquid liquid equilibrium (LLE) for the ternary systems {2-octanone + phenol + water} was experimentally determined at 298.15 K, 318.15 K and 338.15 K under atmospheric pressure. Distribution coefficients and separate factors calculated from the experimental LLE data were used to judge if 2-octanone can be used as potential solvent to extract phenol from aqueous solution. Distribution coefficients and separation factors of 2-octanone were also compared with other extractants and results show that 2-octanone has excellent extraction performance. Binary interaction parameters were regressed by the NRTL and UNIQUAC methods, and related physical meaning is explained by interaction forces. The root mean squared deviations (RMSDs) show that both models can well describe phase equilibrium behavior of ternary system {2-octanone + phenol + water}. In order to predict ternary LLE data at other temperatures, the NRTL model was used to simultaneously regress ternary experimental data at all temperatures and the largest RMSD is 0.49%.

Separation of olefins from FCC naphtha by propylene carbonate: Influence of critical component structure and correlation of ternary LLE thermodynamic models

The separation of olefin from aromatics and sulfides by using propylene carbonate (PC) solvent was studied by the ternary liquid–liquid equilibrium (LLE) of PC + aromatics/sulfide +olefin. The effects of aromatic, sulfide, and olefin structures were investigated by a combination of experiments and quantum chemical calculations. The aromatics and sulfides without side chains were easier to dissolve in PC. Efficient olefin separation was observed because the side chain did not change the positive charge enrichment region of the molecule, and instead increased the steric space when combined with solvent molecules. The olefin separation factor S in the separation of 1-hexene and thiophene is 12.96, which is 1.64 times higher than that in the separation of 1-hexene and 3-methylthiophene. In addition, the binary parameters between the PC and fluid catalytic cracking (FCC) naphtha components for NRTL and UNIQUAC thermodynamic models were obtained using the ternary LLE data to make up for the blank in Aspen simulation for the separation of FCC naphtha by PC solvent. Then, the correlation of NRTL and UNIQUAC models was compared, which the root-mean square deviation (RMSD) of these two models is lower than 0.0043. The NRTL model shows a better correlation with experimental data.

Measurements and correlation of liquid–liquid equilibrium data for the ternary (methyl tert-butyl ketone + o, m, p-benzenediol + water) system at (333.2, 343.2 and 353.2) K

In this work, liquid–liquid equilibria (LLE) data for the ternary system methyl tert-butyl ketone (MTBK) + o, m, p-benzenediol + water were investigated at 333.2 K, 343.2 K and 353.2 K under 101.3 kPa. The performance of MTBK to extract o, m, p-benzenediol from wastewaters was estimated by partition coefficients and separation factors. The Hand and Bachman equations were both applied to check the reliability of the experimental LLE data. Furthermore, the Non-Random Two-Liquid (NRTL) and Universal Quasi Chemical (UNIQUAC) models were applied to correlate the measured LLE data. The results showed a good agreement with the determined ternary LLE data with the root-mean-square error (RMSE) values below 0.71%. MTBK was proved to be a promising extracting agent in extracting benzenediols from effluents.

Equilibrium study for ternary mixtures of biodiesel

The liquid-liquid equilibrium (LLE) data for the ternary mixtures of methanol + fatty acid methyl ester (FAME) + palm oil and FAME + palm oil + glycerol at various temperatures from 35 to 55°C, the tie lines and binodial curves were also investigated and plotted in the equilibrium curve. The experimental results showed that the binodial curves of methanol + FAME + palm oil depended significantly with temperature while the binodial curves of FAME + palm oil + glycerol illustrated insignificant change with temperatures. The interaction parameters between liquid pair obtained for NRTL (Nonrandom Two-Liquid) and UNIQUAC (Universal Quasi-Chemical Theory) models from the experimental data were also investigated. It was found that the correlated parameters of UNIQUAC model for system of FAME + palm oil + glycerol, denoted as a13 and a31, were 580.42K and -123.69K, respectively, while those for system of methanol + FAME + palm oil, denoted as a42 and a24, were 71.48 K and 965.57K, respectively. The ternary LLE data reported here would be beneficial for engineers and scientists to use for prediction of yield and purity of biodiesel for the production. The UNIQUAC model agreed well with the experimental data of ternary mixtures of biodiesel.

Extraction of butan-1-ol from aqueous solution using ionic liquids: An effect of cation revealed by experiments and thermodynamic models

Abstract Production of bio-butanol from biomass by fermentation in an aqueous phase needs new solutions and entrainers for the separation of product. Ionic liquids (ILs) are attractive significant attention as novel, low pressure solvents alternative to conventional organic solvents for biphasic solvent extraction. Ternary liquid-liquid equilibrium data are presented for mixtures of {ionic liquid (1) + butan-1-ol (2) + water (3)} at T = 298.15 K and ambient pressure to analyze the performance of the IL in the extraction of butan-1-ol from aqueous phase. The bis{(trifluoromethyl)sulfonyl}amide-based ILs have been studied: octyltriethylammonium bis{(trifluoromethyl)sulfonyl}amide, [N8,2,2,2][NTf2], methyltrioctylammonium bis{(trifluoromethyl)sulfonyl}amide, [N8,8,8,1][NTf2], 1-dodecyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, [DoMIM][NTf2] and 1-hexyloxymethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, [C6H13OCH2MIM][NTf2]. The results are discussed in terms of the selectivity and the solute distribution ratio of separation for the related systems. The IL with three octyl alkyl chains, [N8,8,8,1][NTf2] at the ammonium-based cation shows higher selectivity and the same distribution ratio in comparison to the other ILs in this process. Additionally, the viscosity of [N8,2,2,2][NTf2], and density and viscosity of the best IL, [N8,8,8,1][NTf2] were measured for the collection of physico-chemical properties of the ILs used in this work. The non-random two liquid NRTL model was used successfully to correlate the experimental tie-lines. The prediction of ternary compositions was shown with good precision using COSMO RS for the ILs used in this work and for data from literature. The data and calculations presented here indicate the possible use of the model COSMO RS for the prediction of ternary LLE and of the use of [N8,8,8,1][NTf2], as a good solvent for the separation of butan-1-ol from water using solvent extraction.

Measurement and Modeling of Liquid–Liquid Equilibrium for the Systems Vinyl Acetate + Acetic Acid/Ethanol + Water at 298.15 and 308.15 K

Liquid–liquid equilibria (LLE) experimental data for the systems of vinyl acetate + acetic acid/ethanol + water were determined at temperatures of 298.15 and 308.15 K and pressure of 101.3 KPa. The reliability of the LLE experimental data was validated by the Bachman and Hand equations. The LLE data of the two systems were fitted by the activity coefficient models of nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC), which the calculated values were in agreement with the experimental tie-line data. Meanwhile, the parameters of the two equations were also determined. Moreover, the distribution coefficients and selectivity values for the two systems were obtained from the ternary LLE data.

Measurement and thermodynamic modeling of ternary (liquid + liquid) equilibrium for extraction of o-cresol, m-cresol or p-cresol from aqueous solution with 2-pentanone

The (liquid+liquid) equilibrium (LLE) data are vital for the liquid extraction of cresols from aqueous solution with 2-pentanone as an extraction agent. Therefore, the ternary LLE data for {2-pentanone+o-cresol, m-cresol or p-cresol+water} were determined at T=(298.15and323.15)K and p=101.3kPa. And the reliability of the LLE data was ascertained by using the Othmer-Tobias and Hand equations. The distribution coefficients and separation factors were calculated to evaluate the effectiveness of extracting cresols from water. The thermodynamic NRTL and UNIQUAC models were used to correlate the experimental LLE data of the studied systems, and the binary interaction parameter values were obtained from the data correlation.

The selectivity of imidazolium-based ionic liquids with different anions to BTX aromatics in hexane at 298.15 K and atmospheric pressure

The selectivity of alkyl-substituted imidazolium cation-based ionic liquids (ILs) with different anion: Tf2N, PF6, Tf2N and BF4, namely 1-Butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide ([BMIM][Tf2N]), 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][Tf2N]), 1-Methyl-3-octyl imidazolium tetrafluoroborate ([OMIM][BF4]), was tested for the extraction of benzene, toluene and p-xylene(BTX) aromatics with hexane mixtures. Liquid-liquid equilibrium (LLE) data were determined for the six ternary mixtures {hexane (1)+BTX (2)+ILs (3)} at 298.15 K and atmospheric pressure. In addition, binary LLE data from 293.15 K to 318.15 K are also reported for the system {hexane (1)+[BMIM][Tf2N] (2)}. The ternary experimental LLE data were satisfactorily correlated with the NRTL activity coefficient model. The degree of consistency of the tie lines was estimated by using the Othmer-Tobias equation, for which a good linear correlation coefficient (R2) was obtained. As a result, the selectivity of ILs as potential solvents for the extraction of BTX from aliphatic components was found to be much higher than unity and PF6 anion showed higher selectivity compared to other anions.

Liquid-liquid equilibrium data for water-ethanol-entrainer ternary system with entrainers: Cyclohexane, n-pentane, DEE (diethyl ether), DIPE (di-isopropyl ether), ETBE (ethyl tert-butyl ether)

The water-ethanol system was studied experimentally to find the liquid-liquid equilibrium (LLE) data at various temperature values by using five different entrainers: cyclohexane, n-pentane, DEE (diethyl ether), DIPE (di- isopropyl ether), and ETBE (ethyl tert-butyl ether). Ternary LLE data for water-ethanol-entrainer system was deter- mined based on an experimental procedure. Exact liquid activity coefficient parameters were found by experimental data and LLE data was predicted. For this purpose, two thermodynamic models, NRTL and UNIQUAC, were com- pared and contrasted with experimental data to probe into the better thermodynamic model for the azeotropic processes of ethanol system. The most promising entrainer was found through root mean square and average absolute deviations.

Liquid–Liquid Equilibrium for the Ternary System 2,2,3,3,4,4,5,5-Octafluoro-1-pentanol + Ethanol + Water at (298.15, 308.15, and 318.15) K

Liquid–liquid equilibrium (LLE) data for the ternary system 2,2,3,3,4,4,5,5-octafluoro-1-pentanol + ethanol + water have been reported at (298.15, 308.15, and 318.15) K and 0.1 MPa. The Bachman equation and the Hand equation were used to confirm the reliability of the experimental tie-line data. The experimental data were correlated by the nonrandom two-liquid (NRTL) model, for which the calculated results show good agreement with the ternary LLE data, and the binary interaction parameters of NRTL model were also regressed. Moreover, the distribution coefficients and separation factors in the ternary system were determined by the experimental data.

Correlation of liquid–liquid equilibrium for binary and ternary systems containing ionic liquids with the tetrafluoroborate anion using ASOG

Ionic liquids are neoteric, environmentally friendly solvents (since they do not produce emissions) composed of large organic cations and relatively small inorganic anions. They have favorable physical properties, such as negligible volatility and wide range of liquid existence. Liquid–liquid equilibrium (LLE) data for systems including ionic liquids, although essential for the design, optimization and operation of separation processes, are still scarce. However, some recent studies have presented ternary LLE data involving several ionic liquids and organic compounds such as alkanes, alkenes, alkanols, water, ethers and aromatics. In this work, the ASOG model for the activity coefficient is used to predict LLE data for 15 binary and 09 ternary systems at 101.3kPa and several temperatures; all the systems are formed by ionic liquids including the tetrafluoroborate anion plus alkanes, alkanols, water, ethers, esters and aromatics. New group interaction parameters were determined using a modified Simplex method, minimizing a composition-based objective function of experimental data obtained from literature. The results are satisfactory, with rms deviations of about 3%.

Liquid–liquid equilibria in the ternary systems {hexadecane + BTX aromatics + 2-methoxyethanol or acetonitrile} at 298.15 K

The liquid–liquid equilibrium (LLE) data were determined for the ternary systems {hexadecane+benzene+2-methoxyethanol}, {hexadecane+toluene+2-methoxyethanol}, {hexadecane+p-xylene+2-methoxyethanol}, {hexadecane+benzene+acetonitrile}, {hexadecane+toluene+acetonitrile} and {hexadecane+p-xylene+acetonitrile} at 298.15K and atmospheric pressure. From the LLE data, the selectivity of 2-methoxyethanol and acetonitrile was analyzed to test solvent capability for the separation of aromatic compounds from (aliphatic+aromatic) mixture. The experimental ternary LLE data correlated well with the NRTL and UNIQUAC activity coefficient models with a root mean square deviation (RMSD) of less than 1%. The reliability of the experimental tie line data was ascertained by using the Othmer–Tobias correlation. The selectivity of 2-methoxyethanol and acetonitrile for BTX aromatics was found to be dozens of times more than the unity for both solvents, especially for low concentrations of aromatic compounds.

Liquid–liquid equilibria for ternary system water + acetic acid + cyclohexanone at (293.2–323.2) K

Liquid–liquid equilibria (LLE) for the ternary system water+acetic acid+cyclohexanone was studied at (293.2–323.2)K and at atmospheric pressure. The immiscibility region was found to be relatively small and not sensitive to the change of temperature. The Othmer–Tobias equation and the Bachman equation were both used to check the reliability of the obtained experimental tie-line data. The experimental results were correlated with both the NRTL and the UNIQUAC activity coefficient models. The calculated results showed good agreement with the experimentally determined ternary LLE data. The root mean square deviations (RMSD) obtained by comparing the calculated and experimental two-phase compositions are 0.72% for the UNIQUAC model and 0.40% for the NRTL model. The obtained interaction parameters can be used in the calculation of LLE for the ternary system water+acetic acid+cyclohexanone as well as for the design and optimization of the related separation process.

Influence of hydroxyl group for thermoresponsive poly(N-isopropylacrylamide) gel particles in water/co-solvent (1,3-propanediol, glycerol) systems

The influence of the addition of a co-solvent in an aqueous poly(N-isopropylacrylamide) (PNIPA) solution was investigated based on a thermodynamic framework, which considers the modified double lattice (MDL) theory of mixing and the Flory–Rehner (FR) chain model for the elasticity. The cloud points for the ternary system of PNIPA (1)/water (2)/propane-1,3-diol (1,3-PDO) and glycerol (3) were measured by thermo-optical analysis (TOA) and the swelling behaviors of nanometer-sized PNIPA gel particles were determined using photon correlation spectroscopy (PCS). Completely different results were obtained depending on the number of hydroxyl groups of the co-solvent. For glycerol, which has three hydroxyl groups, added in aqueous PNIPA, the volume transition temperature of the PNIPA gel particles continuously decreased. On the other hand, the addition of 1,3-PDO, which has two hydroxyl groups, resulted in an increased volume transition temperature of the gel. To determine the molecular interaction parameters, we utilized a step-by-step approach. First, a secondary lattice theory of specific interactions was employed to correlate the binary liquid–liquid equilibrium (LLE) of PNIPA in water and was directly applied to our ternary LLE data to obtain the remaining interaction parameters. Secondly, composition dependence of the energy parameter was adopted to describe the swelling behaviors of PNIPA gel particles in the water/co-solvent system. The method presented here provides an understanding of the thermodynamics of polymers and polymer gel in mixed solvents.

Liquid–Liquid Equilibria for Ternary Mixtures of Methylphenyl Carbonate, Dimethyl Carbonate, Diphenyl Carbonate, Anisole, Methanol, Phenol, and Water at Several Temperatures

The ternary liquid–liquid equilibria (LLE) at atmospheric pressure of the following systems have been studied at several temperatures in stirred, thermo-regulated cells: water + anisole + methyl phenyl carbonate (MPC) at 308.15 K, water + methanol + MPC at 308.15 K, water + dimethyl carbonate (DMC) + MPC at 308.15 K, water + phenol + MPC at 318.15 K, and water + diphenyl carbonate (DPC) + MPC at 358.15 K. The experimental ternary LLE data have been satisfactorily correlated with the well-known two activity coefficient models: the Non-Random Two-Liquid (NRTL) and UNIversal QUAsiChemical (UNIQUAC). In addition, the distribution coefficients and the selectivity values of MPC for anisole, methanol, DMC, phenol, and DPC were derived from the tie-line data.

Liquid-Liquid Equilibria of Water + Lacticacid + Butylacetate

Experimental liquid-liquid equilibria of the ternary system of (water + lactic acid + butyl acetate) were studied at T=(298.15, 303.15 and 308.15) K under atmospheric conditions. Complete phase diagrams were obtained by determining solubility and tie-line data. The ternary system exhibits type-1 behavior of LLE. The reliability of the experimental tie-line data was ascertained by using both Hand and Othmer-Tobias correlations. The UNIFAC group contribution method was used to predict the observed ternary liquid-liquid equilibrium data. Distribution coefficients and separation factors were evaluated to evaluate the extracting capability of the solvent. Separation factors were more than unity and the UNIFAC prediction was satisfactory.

Experimental measurement and modeling of the Type 3 ternary system containing (decane + water + triacetin)

Experiments were conducted to establish the phase diagram for the ternary system containing (n-decane+water+triacetin) at T=296.15K and ambient pressure. Results indicated that this system belongs to Type 3 Treybal classification with a (liquid+liquid+liquid) equilibrium (LLLE) region. Five sets of NRTL parameters were determined using a combination of different objective functions and datasets (binary and ternary). A new objective function based on Gibbs energy minimization and a phase calculation scheme specific for Type 3 ternary systems were developed. Results indicated that the NRTL model can satisfactorily predict the ternary behavior of the system and could accurately correlate binary (liquid+liquid) equilibria (LLE), ternary LLE and ternary LLLE data simultaneously.