Tie-line Data Research Articles

Ternary Liquid-Liquid Equilibria in a Few Nonaqueous Two-Phase Systems

AbstractThe composition of coexisting phases for liquid-liquid and solid-liquid-liquid equilibria were measured at 298.2 and 313.2 K and under atmospheric pressure for the following systems: {sodium bromide + formamide + ethyl acetate}, {sodium thiocyanate + ethanol + (R)-limonene}, and {sodium thiocyanate + methanol + dibutyl ether}. These concentrations were determined mainly by chromatography and, for the first system, with the help of argentometric titration. The standard uncertainties in mole fractions varied between 0.001 and 0.008. The tie-line data were reproduced by the NRTL model with medium accuracy. Several empirical equations were used and tested to correlate binodal curves. The rational form of the equation, based on the liquid–liquid–solid tie-line, turned out to be the most adequate.

Three-liquid-phase behavior in the quaternary systems of water + phosphoric acid + diisopropyl ether + tributyl phosphate/methyl isobutyl ketone at 298.2 K

The three-liquid-phase formation in the ternary system of water + phosphoric acid + diisopropyl ether (DIPE) makes the phosphoric acid extraction only effective for acid mass fractions above 0.69. To avoid the undesirable formation of the third phase and enhance acid extraction, particularly at low concentrations, two phase modifiers, methyl isobutyl ketone (MIBK) and tributyl phosphate (TBP), were systematically studied. In order to quantify the synergetic effect of the mixed solvents of DIPE+TBP and DIPE+MIBK, the liquid–liquid equilibria for the quaternary systems of H2O+H3PO4 + DIPE+TBP and H2O+H3PO4 + DIPE+MIBK were fully established for different DIPE/phase modifier (TBP or MIBK) mass ratios (90/10, 70/30, 50/50, and 20/80) at 298.2 K under atmospheric pressure using the cloud point and Othmer graphical method. Othmer-Tobias and Hand correlations were used to fit the tie-line data and assess its consistency. In addition, the behavior of the three-phase zone was also studied as a function of the phase modifiers content. Separation factor (S) and acid distribution (D2) were used to identify the most effective solvent with the potential to enhance phosphoric acid extraction from aqueous solutions.

Removal of phenolic compounds from aqueous solution using Hydrophobic deep eutectic Solvent: Liquid-Liquid phase behavior and intermolecular interactions

Hydrophobic deep eutectic solvent (HDES, menthol: decanoic acid: octanoic acid = 1:1:1), as a green and eco-friendly solvent was evaluated for the extraction of the phenolic compounds (phenol, m-cresol, and o-cresol) in terms of their toxicity in water. The liquid-liquid equilibrium (LLE) data for the mixtures (water + phenol / m-cresol / o-cresol + HDES) were determined at a temperature of 298.15 K and 101.3 kPa. The efficacy of HDES as an extractant was evaluated by computing the selectivity (S) and distribution coefficient (D). The calculated values of D and S, greater than unity, showed that the extraction of phenol, m-cresol, and o-cresol from water by HDES is feasible. The results indicated that HDES performs better for the extraction of m-cresol and o-cresol from their aqueous solutions than phenol. The tie-line data were fitted using the NRTL model, with calculated RMSD values less than 0.0104, indicating the model’s suitability for representing the mixtures. Furthermore, the interactions between HDES and phenol / m-cresol / o-cresol were studied by calculating the molecular electrostatic potentials, interaction energy, and reduced density gradient. Quantum chemical calculations showed that the interaction between m-cresol and o-cresol with HDES is more favorable than that of phenol.

Study of quaternary liquid-liquid equilibria for systems (water/ methanol/ cyclohexanol+ toluene): Experimental and modelling

The experimental liquid-liquid equilibrium (LLE) data for the extraction of methanol from aqueous solution using mixed solvents (toluene + cyclohexanol) at 291.15 K and atmospheric pressure at the ratios (0, 0.25, 0.4, 0.6, 0.8, 1) was studied. The values of the solvent ratio 0 and 1 led us to study the liquid-liquid equilibrium of the ternary systems (water/methanol/cyclohexanol) and (water/methanol/toluene). The compositions of the coexisting phases were determined by the cloud point method. The tie line data for ternary and quaternary systems were correlated by NRTL model. The Othmer-Tobias and Hand correlations were also tested, to verify the reliability of the experimental tie lines data. The separation factor and the distribution coefficient were calculated from the experimental data to evaluate the effect of using mixed solvents. It was found that the ratio M = 0.4 is the best suited for the liquid-liquid extraction of methanol from water.

Hybrid process for separation of morpholine−water mixture: A rigorous design with experimental confirmation based on LLE and VLE data

The separation of morpholine from the aqueous effluent stream is carried out using an efficient hybrid extraction-distillation (HED) system using commercially viable solvents 2-ethyl hexanol and toluene, which makes heteroazeotrope with water. This paper investigated the tie-line, mutual solubility and VLE measurements, and thermodynamic modeling. On comparing the two solvents, 2-ethyl hexanol emerged as an appropriate extractant. The experimental tie-line data regressed by the NRTL model and a deviation of 0.8 indicates a good correlation between experimental and predicted data. Further, the process is designed, simulated, and optimization is performed by minimizing total annual cost (TAC) as the objective function. At extract/solvent to feed ratio S/F of 0.78 mol fraction, number of stages, NT of 28, 99.8% morpholine recovered in the extract phase with TAC of $23.3×104/y. Subsequently, the extract phase is fed to the heteroazeotropic distillation column to remove moisture followed by the final recovery column. Finally, a laboratory-scale experiment was conducted to verify the separation performance in the downscaled (3.5×50 cm) counter-current extraction column.

Application of deep eutectic solvent-based aqueous two phase systems for extraction of analgesic drugs.

The ability of biphasic-aqueous systems to efficiently and simultaneously purify active pharmaceutical compounds has led to extensive study of these systems. As a new environmentally friendly separation technology, deep eutectic solvent (DES)-based aqueous two-phase systems (ATPSs) are extensively applied for the extraction and separation of various bioactive compounds. In this study, two DES-based ATPSs consisting of choline chloride/fructose and choline chloride/glucose as DESs with a molar ratio of 2 : 1 and tripotassium phosphate (K3PO4) were prepared. The measured binodal data correlated with Merchuk and Zafarani-Moattar et al. equations. Moreover, the ATPSs were employed to investigate the separation of pharmaceuticals. The partition coefficient and the effect of factors such as the concentration of the deep eutectic solvent on drug partitioning were investigated as novel discoveries. Drugs are likely to be removed in the top DES-rich phase, according to the current data. Finally, the compositions of five tie-lines for each ATPS were meticulously determined. Othmer-Tobias, Bancraft, and Setschenow equations were used for correlation of tie-line data.

Liquid-liquid equilibria of Aliquat 336 + green solvents + water for replacement of petroleum-based solvents: Intramolecular analysis and thermodynamic behavior

The investigations of Aliquat 336 dissolved in green solvents: corn oil, rice bran oil, and sunflower oil, compared with toluene and kerosene to replace the petroleum-based solvents. Liquid-liquid equilibria of adjusted pH water + Aliquat 336 + solvents were evaluated at 303.2 K, 313.2 K, and 323.2 K and 0.1 MPa. The mass fraction of Aliquat 336 was carried out in the range 25–75 wt%. The performance of solvents was explored through the distribution coefficient (D) and selectivity factor (S). The Van’t Hoff, Jouybran – Acree model, modified Jouybran - Acree - Van’t Hoff, and nonrandom two liquid (NRTL) models were investigated. The mixed Gibbs free energy topology (GM(L)) analysis was applied to verify the accuracy of binary interaction parameters from the model. It is seen that corn oil at 303.2 K proved to be the most efficient solvent to dilute Aliquat 336. As verified by the good, correlated root mean square deviations and the GM(L) analysis, the NRTL model fits in well with the tie-line experimental data. The density functional theory reveals the stronger molecular interaction between Aliquat 336 and green oils than petroleum-based solvents. In line with the properties effect, the dielectric constants and viscosity are seen to further support the experimental results.

Measurements, correlations and thermodynamic modeling of aqueous two-phase systems of polyvinylpyrrolidone (PVP) + sulfate/citrate salts

Aqueous two-phase systems (ATPS) can be described as an alternative to traditional liquid-liquid extraction systems, typically consisting of a polymer and a salt solution. An alternative polymer called polyvinylpyrrolidone (PVP) has emerged as a viable option for ATPS due to its low cost, stability, and potential. This study aimed to investigate the effect of the molecular weight of poly (vinylpyrrolidone) (PVP) (K17, K25, and K30) and the temperature (298.15, 303.15, and 308.15 K) in the system ATPSs composed of PVPs and sodium sulfate/potassium sulfate/tri sodium citrate. The tie-line data were determined by measuring the density (ρ) and refractive index (nD). Moreover, the phase compositions and plait point are investigated for different PVPs molecular weight, temperature, and salt type. In addition, the effect of these parameters on the binodal curve, tie-line length (TLL), and slope of tie line (STL) are analyzed in detail by comparing them with the literature data. The impact of the parameters on the binodal curves was investigated by utilizing the values of the effective excluded volume parameter (EEV) that were calculated from the LLE data. Furthermore, the binodal curves and the tie-line compositions were well-fitted by using some semi-empirical equations. The phase separation ability is enhanced with temperature and PVPs molecular weight. The modified UNIFAC-NRF is used to correlate the liquid-liquid equilibrium data of the studied systems and the optimized binary group interaction parameters were determined.

Liquid-liquid equilibria of ternary mixtures containing Aniline + Toluene + water at elevated temperatures: measurements and correlation

ABSTRACT Liquid-liquid equilibrium (LLE) data for the ternary system, Aniline + Toluene + Water, was measured at different temperatures of 298.15 K, 313.15 K and 323.15 K under atmospheric pressure with the help of High-Performance Liquid Chromatography (HPLC) analysis and Karl-Fischer technique. The efficiency of Toluene to extract Aniline from aqueous phase was then quantified in terms of the distribution coefficient and separation factor based on the tie line data. The system showed very good separation ability quantified in terms of high values of distribution factor (average around 7) and separation factors (as high as 1000). The experimental tie line data was verified by Hand and Othmer-Tobias equations. The LLE data was also correlated using NRTL and UNIQUAC models and both of them were able to represent the behavior of the system accurately when tested against experimental results. Toluene has been demonstrated to be very efficient to extract Aniline from reaction mixture, which is typically a by-product in hydrogenation of nitrobenzene, a process commercially used to produce p-Aminophenol in industry.

Ionic liquid promoted extraction of gold(III) from electronic waste: a modeling study

ABSTRACT Being an expensive metal, the large-scale requirement of gold in the ever-growing market of electronics increases the overall cost of manufacturing. Hence, recycling gold from electronic waste mitigates the demand and subsequently bounds the price of electronic goods. However, the extraction of gold from electronic waste poses a severe hazard to the environment. Because of tuneable and fascinating properties, ionic liquids (ILs) have emerged as state-of-the-art solvents to extract gold from electronic waste. Herein, the modeling of IL-assisted liquid-liquid-extraction incorporating UNIQUAC extended Pitzer–Debye–Hückel* (PDH*) thermodynamic model has been used for the extraction process of gold from an aqueous acidic solution. The long-range, weak electrostatic interactions present in ionic liquids are adequately represented by the extended PDH* model. The model parameters are obtained from the polarizable continuum medium (PCM) calculation, conductor-like screening model for real solvent (COSMO-RS), and genetic algorithm formulation. Altogether, 11 hydrophobic ILs consisting of 9 imidazolium, 1 pyrrolidinium, and 1 ammonium class with 51 tie line data points are considered for the modeling. The estimated root mean square deviation of 0.002–0.99% over 51 tie lines reveals the goodness of the fitting. The projected percentage extraction efficiency lies in the range of 98.5% to 99.3%.

Research on separation sulfides from fuel oil using sulfolane: Liquid-liquid equilibrium and mechanism exploration

Separation of sulfides from fuel oil is of great significance for environmental protection. In this paper, the organic solvent (sulfolane) was selected to separate sulfides (thiophene and 2-methylthiophene) from model fuel oil (n-heptane). The liquid–liquid equilibrium data of the mixtures (n-heptane + thiophene/2-methylthiophene + sulfolane) were measured at 303.15, 313.15 and 323.15 K under 101.3 kPa. The mass conservation of the experimental data were checked, and the reliability of the tie-lie data were evaluated by the Bachman, Hand and Othmer-Tobias equations. The extraction performance of sulfolane was assessed through the separation factor and partition coefficient, and compared with those for other reported solvents, indicating that sulfolane has better extraction performance for thiophene compared with 2-methylthiophene. Then, the quantum chemical calculation was applied to found the separation mechanism of sulfolane. The analysis of electrostatic potential, interaction energies, and reduced density gradient showed that the main interactions between sulfolane and thiophene (or 2-methylthiophene) were van der Waals and weak hydrogen bond forces. Finally, the non-random two-liquid theory (NRTL) and universal quasi-chemical theory (UNIQUAC) models were applied to fit the tie-line data of the investigated mixtures with the root-mean-square deviation (RMSD) lower than 0.01. The mixed surface analysis method based on Gibbs energy topology is used to verify the binary interaction parameters, which provides basic data for simulating the separation process of sulfide in fuel oil.

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.

Liquid–Liquid Equilibrium for Ternary Systems 2,2,2-Trifluoroethanol + Water + (Ethyl Acetate/Isopropyl Acetate/Isobutyl Acetate) at 308.15 K under 101.3 kPa

2,2,2-Trifluoroethanol (C2H3F3O, TFE) is a useful fluorine-containing alcohol. During the synthesis and application of TFE, TFE, and water can form an azeotropic mixture. To recover TFE from the mixture of TFE and water by liquid–liquid extraction (LLET), in the current work, three organic solvents, isobutyl acetate (C6H12O2), isopropyl acetate (C5H10O2), and ethyl acetate (C4H8O2), were chosen as the extractants. The liquid–liquid equilibrium (LLE) behavior for the three mixtures (water + TFE + ethyl acetate/isopropyl acetate/isobutyl acetate) was investigated at 101.3 kPa and 308.15 K. Selectivity (S) and distribution constant (D) were calculated as indexes to evaluate the extraction capacity of the three extractants. The results indicated that isobutyl acetate has better extraction ability in extracting TFE from its aqueous solution of TFE compared to the esters. The NRTL model was used to regress the determined tie-line data. The coherence of the fitted parameters of the NRTL model with the experimental data was checked by topological analysis.

Biological Buffer Effect on Liquid–Liquid Equilibria of Systems Containing n-Butanol + Methyl Isobutyl Ketone + Water

Biofuel, that is, n-butanol, production from plant-based biomass represents a renewable energy resource that can be a substitute for fossil fuel. Thus, it is important to study the separation of n-butanol from its aqueous solution to obtain a high-purity product. Liquid–liquid extraction is a beneficial process in alcohol production to recover alcohol from the aqueous medium. Liquid–liquid equilibrium (LLE) data are needed for rational design and optimal separation operation, such as biological separation and extraction processes. The objective of this study is to determine LLE data for quaternary systems of n-butanol, methyl isobutyl ketone (MIBK), water, and a biological buffer at 303.15 K and atmospheric pressure (P = 0.1 MPa). The effect of biological buffer addition into aqueous solution was also studied. Three different biological buffers, 4-(2-hydroxyethyl)-1-piperazine propanesulfonic acid (EPPS), 4-morpholinepropanesulfonic acid (MOPS), and 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), were applied in this study for the comparison. The separation factor and distribution coefficient were evaluated in this study to interpret the extraction performance of n-butanol. According to the experimental results, the extraction performance was in the order of HEPES > EPPS > MOPS, describing the strength of buffering-out as well. Furthermore, it was found that the aid of a biological buffer in the LLE systems consisting of n-butanol, MIBK, and water resulted in better extraction performance than that of the LLE systems in the absence of a biological buffer. The reliability of the experimental LLE tie-line data was satisfactorily ascertained by the Hand correlation. The non-random two-liquid and universal quasi-chemical thermodynamics models correlated well the experimental LLE tie-line data with the root mean square deviation of less than 1%. The binary interaction parameters of both models were also obtained in this study.

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.

Phase Equilibria of the Ternary System of Lithium Sulfate + Polyethylene Glycol (PEG3000) + Water at Different pH: Experiment Determination, Correlation, and Thermodynamic Modeling

The phase equilibrium data for the ternary systems [lithium sulfate (Li2SO4) + polyethylene glycol (PEG3000) + water] were measured at 298.15 K and at various pH values (2.94, 4.90, and 6.80). The solid–liquid equilibrium data including the solubility, density, and refractive index were determined using the isothermal dissolution equilibrium method. The liquid–liquid equilibrium (LLE) data for the aqueous two-phase system were obtained experimentally by measuring the biphasic physical properties, including the density and refractive index at 298.15 K. Subsequently, the binodal curves were correlated by using the Pirdashti and Merchuk equations, the effective excluded volumes were calculated from the binodal curve data, and the tie-line compositions were adjusted to the Othmer–Tobias and Bancroft equations, respectively. Results show that the solubility of Li2SO4 in the aqueous polymeric solution mitigates as the content of PEG increases, eventually. It was found that the more acidic solution induces the salting-out effect, and the LLE formed easily at the lower pH of studied systems. Finally, the extended UNIQUAC, the modified UNIQUAC-FV, and the modified UNIFAC-NRF models were selected to correlate the LLE data of the studied systems, and the modified UNIQUAC-FV model gives a better correlation for tie-lines data.

Ternary Liquid-Phase Equilibria of an Azeotropic Mixture (Heptane + Isopropyl Alcohol) with Deep Eutectic Solvents

The present study reports the result of the measurement and analysis of the solubility curve and tie-line data of four ternary systems containing heptane–isopropyl alcohol azeotrope mixtures and deep eutectic solvents (DESs) at T = 298.2 K and p = 0.1 MPa. This investigation is aimed to evaluate the efficiency of the prepared DESs as extractants in the separation of the heptane–alcohol azeotropic mixtures through liquid–liquid extraction (LLE) processes. In this study, four choline chloride-based DESs were prepared by a heating process. Two hydrogen bond donor (HBD) compounds (i.e., ethylene glycol and propylene glycol) were chosen in the preparation of the DESs. The solubility curves show that the effect of DESs on the immiscibility region is small. The studied systems display the type-1 LLE behavior. The measured tie-line values were adequately fitted through the nonrandom two-liquid (NRTL) thermodynamic model, and the interaction parameter values were determined. The correlation data appeared to be in good agreement with the measured tie-lie data. The extraction capacity (distribution constants and selectivities) of the studied DESs was determined. The DESs had high and similar selectivity values for the studied systems. Moreover, the distribution constants were larger than unity, indicating a favorable solvent-to-feed ratio.

EXTRACTION OF ETHANOL FROM AQUEOUS SOLUTION USING 1-HEXANOIC ACID AND 1-NONANOIC ACID

Ternary phase equilibrium data for ethanol-water-1-hexanoic acid and 1-nonanoic acid were experimentally obtained with a view to evaluate the possibility of separation of ethanol from aqueous solutions by distributing each between water and ethanol phases. The mutual solubility curves, tie lines and plait points were constructed from the experimental results. Distribution coefficients and separation factors were computed for these systems. Hand’s method was used to correlate tie lines and to calculate coordinates of plait points. Tie line data were satisfactorily correlated by the Othmer-Tobias method on a mass fraction basis.

Measurement and Correlation of the Liquid-Liquid Equilibria of Tertiary-Butyl Alcohol – Water – Benzene System at 30°C and 1 Atmosphere Pressure

The Liquid-Liquid equilibria of Tertiary-Butyl Alcohol – Water – Benzene System were measured experimentally at 30°C and 1atm pressure. The experimental binodal curve compositions were obtained using the cloud point method. The compositions of the two equilibrium phases were analysed using Agilent 7820A series Gas Chromatograph. The consistency of the experimental data was determined using the Hand, Othmer-Tobias and Bachman- Brown correlation equations while the plate point was determined using the Treybal’s method. The effectiveness of the solvent in the extraction was determined by calculating the distribution coefficients and separation factors. The experimental tie-line data were correlated with the Universal Quasi-Chemical (UNIQUAC) and Non-Random Two Liquid (NRTL) activity coefficient models. Also, the deviation between the experimental and calculated equilibrium compositions were calculated using the root mean squared deviation equation. The UNIQUAC predicted data gave a closer resemblance to the experimental.

Liquid-liquid phase equilibria for the ternary (neopentyl glycol + sodium formate + water) system

ABSTRACT. Liquid–liquid equilibrium data and the phase diagrams were measured for the ternary (neopentyl glycol + sodium formate + water) system at various temperatures of 303.15, 313.15 and 323.15 K. The effect of temperature on the conjugate phase and the tie-line length of the investigated system have been studied. The results showed that the length of the tie-line increases and the two-phase area was slightly increased by decreasing temperature. The fitting parameters of the Pirdashti and Merchuk equations were obtained with the temperature dependence expressed in the linear form, respectively. Compared with the Pirdashti equation, the binodal curves were satisfactorily described using the Merchuk equation at T = (303.15, 313.15 and 323.15) K, and the critical points at different temperatures were estimated by extrapolation. Furthermore, the Hand, Othmer-Tobias and Bachman models were used for the correlation of the phase behavior of the studied system. According to the reported correlation coefficients values, it was found that the measured tie-line data have acceptable consistency and the better fitness was with Othmer-Tobias equation. &#x0D; &#x0D; KEY WORDS: Liquid–liquid equilibrium, Neopentyl glycol, Phase diagram, Merchuk&#x0D; Bull. Chem. Soc. Ethiop. 2022, 36(4), 915-922. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v36i4.16