Experimental Tie-lines Research Articles

Investigation of non-equilibrium separation time on the partitioning of cephalexin in an aqueous two-phase system composed of glucose and acetonitrile

Abstract In order to commercialize aqueous two-phase systems (ATPSs), not only the equilibrium data is essential, but also the knowledge of separation mechanisms, kinetics, settling time, and operational conditions are needed. Mixing duration and settling time are the most critical factors affecting separation and biomolecule partitioning in terms of economic aspects. This research aimed to find the desired conditions for separating cephalexin in an ATPS consisting of acetonitrile, glucose, and water. Firstly, the evolution of the interphase region was observed. Hereafter, to examine the effect of time on the experimental tie-lines and partition coefficient in non-equilibrium states, the settling time was varied from 2 min to 24 h. In addition, centrifugation was applied to help the separation at different time intervals and rotational speeds. The results of tie-lines slope and partitioning coefficients showed that the system approaches equilibrium after 5 h. However, using the centrifuge separation at 4000 rpm improved the separation time to 45 min, reaching 80 % of the actual partition coefficient. It can be concluded that with an acceptable tolerance in the partition coefficient, a remarkably diminished settling time is available for economic productivity in industrial units.

Comparative study of liquid–liquid equilibria for aqueous mixtures of lactic acid with structurally similar cyclic and non-cyclic ketones

Liquid-liquid equilibria (LLE) were studied and compared for the aqueous mixtures of lactic acid (L(+) enantiomer) with the two structurally similar α,β-unsaturated ketones (mesityl oxide or isophorone)} at 298.2, 308.2, and 318.2 K and 101.3 kPa. Due to the close structural similarity of the chosen solvents, an experimental and correlational study was systematically carried out on performance of mesityl oxide and isophorone to extract l-lactic acid from water. The ternary systems exhibit type-1 behavior of LLE. The thermodynamic models of NRTL and UNIQUAC were successfully applied to fit the experimental tie-lines and the model binary interaction parameters were determined. The consistency of the calculated NRTL parameters was validated and qualified through topological analysis connected to the Gibbs tangent principle and stability test. Evaluation of the capacity of each solvent was performed using the calculation of distribution coefficients and separation factors. The influence of extraction temperature and the chemical structure of the solvent on the immiscibility region were found to be small. As a result, the selectivities specify that both the cyclic and non-cyclic ketones were found to be promising extractants for the separation of lactic acid from its dilute aqueous solutions.

Thermodynamic study of ATPS involving ethyl lactate and different inorganic salts

• Novel ethyl lactate-based Aqueous Two-Phase Systems were studied. • Pitzer-Debye-Hückel + UNIQUAC thermodynamic modelling of experimental ATPS data was carried out. • The experimental binodal data and tie-lines compositions were successfully fitted using several empirical equations. In this work, three Aqueous Two-Phase Systems (ATPS) involving ethyl lactate and the inorganic salts (NH 4 ) 2 SO 4 , K 2 HPO 4 and NaH 2 PO 4 have been studied. To analyse the separation process, binodal curves and tie lines were experimentally determined at T = 298.15 K and atmospheric pressure. The experimental binodal data were successfully fitted using several empirical equations: Merchuk et al. , Hu et al. , Han et al. and Jayapal et al. , and the degree of consistency of the tie line compositions was evaluated using Othmer-Tobias and Brancoft equations. The liquid–liquid equilibria were fitted using the Pitzer-Debye-Hückel + UNIQUAC and the UNIQUAC thermodynamic models. For all systems, the modelled tie lines were very similar to the experimental ones, but the first model presented somewhat smaller deviations, which allows to conclude that long-range forces present in these systems with strong salts should be considered.

Phase equilibria liquid-liquid for ternary systems n-amyl alcohol – water – (acetic acid, n-amyl acetate), n-amyl acetate – water – acetic acid at 293.15 K, 303.15 K, 313.15 K and 323.15 K

Experimental data on liquid-liquid equilibrium for the ternary systems acetic acid – n-amyl alcohol – water, acetic acid – n-amyl acetate – water, n-amyl alcohol – n-amyl acetate – water and for the quaternary system acetic acid – n-amyl alcohol – n-amyl acetate – water at 293.15 K, 303.15 K, 313.15 K and 323.15 K and atmospheric pressure were obtained by gas chromatography method. Phase diagrams are presented using Gibbs composition triangle and composition tetrahedron. Sufficient agreement of experimental tie-lines with calculated by NRTL model is observed: standard deviation does not exceed 1.2%.

Application of deep neural network (DNN) for experimental liquid-liquid equilibrium data of water + butyric acid + 5-methyl-2-hexanone ternary systems

LLE data are important for simulation and design of extraction equipment. In this study, deep neural network (DNN) structure was proposed for modelling of the ternary liquid-liquid equilibrium (LLE). LLE data of (water + butyric acid + 5-methyl-2-hexanone) ternaries defined at three different temperatures of 298.2, 308.2, and 318.2 K and P = 101.3 kPa, were obtained experimentally and then correlated with nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models. The performance of the proposed DNN model was compared with that of NRTL and UNIQUAC in terms of the root mean square errors (RMSE). RMSE values were obtained between 0.02-0.06 for NRTL and UNIQUAC, respectively. For DNN, the error values were obtained between 0.00005-0.01 for all temperatures. According to the calculated RMSE values, it was shown that proposed DNN structure can be better choice for the modelling of LLE system. Othmer-Tobias and Hand correlations were also used for the experimental tie-lines. Distribution coefficient and separation factors were calculated from the experimental data.

Necessity of imposing total miscibility for certain binary pairs in LLE data correlations

Liquid-liquid equilibrium (LLE) data correlation of multicomponent mixtures is frequently carried out without using any procedure to ensure that the model parameters obtained for the totally miscible binary mixtures are consistent with such behavior (i.e. they do not lead to two liquid phases in equilibrium). In other words, the behavior of the model beyond the LLE region fitted (experimental tie-lines) is not usually considered in LLE correlations. It seems to be wrongly assumed that the mere absence of tie-lines data in totally miscible regions should guarantee that the parameters resulting from the LLE correlation lead to total miscibility in such homogeneous regions. We have checked that for the correlation of certain type 1 ternary systems (Treybal classification) a high probability exists of obtaining inconsistent model parameters, which lead to type 2 instead type 1 ternary behavior, unless specific restrictions for such parameters are imposed during the correlation. Commercial tools to carry out this type of data fitting, which are frequently included in process simulation packages such as Aspen Plus, do not include the possibility of applying such restrictions and consequently they could provide this type of misleading correlation results with serious consequences in equipment design. In the present paper, LLE data correlation for certain type 1 ternary systems has been carried out using Aspen Plus resulting in inconsistent type 2 results. These same systems have been satisfactorily correlated using our own correlation tools including restrictions to ensure the required miscibility behavior, and thus obtaining consistent parameters. A similar problem could occur in the correlation of the less frequent island (or zero) type ternary systems. Some examples are also presented for such type of systems.

Measurement and Correlation of LLE Data for the Ternary System Water+Phosphoric Acid+1-Pentanol at 278.2 K and 288.2 K

In this study, experimental tie-line data analysis was conducted for the ternary system (water+phosphoric acid+1-pentanol) at 278.2 K and 288.2 K and atmospheric pressure. The compositions of equilibrium phases were determined using the acid-base and the Karl Fisher titration methods and mass balance calculations. Reliability of the experimental data was investigated using the Othmer–Tobias and Hand equations. The UNIQUAC thermodynamic model was applied for correlation of the equilibrium tie-line points. The experimental tie-lines were satisfactorily regressed using the thermodynamic model (%rmsd=2.48). Distribution coefficients and separation factors were determined over the biphasic area. Separation factors were greater than one in all the investigated feeds at the studied temperatures that guarantees the successful separation process. The Kamlet-Taft parameters were applied for the LSER modeling of the obtained distribution coefficients and separation factors. The effect of temperature on extraction process was investigated by adding a modification term in Kamlet-Taft equation. The ternary system revealed good fittings with the modified LSER model. The results showed that, the temperature decrement had positive effect on the extraction ability of the 1-pentanol for separating phosphoric acid from aqueous solution.

Separation of organosulfur compounds from heptane by liquid–liquid extraction with tricyanomethanide based ionic liquids. Experimental data and NRTL correlation

This work is an attempt to determine appropriate solvents for extractive desulfurization, which is the dominant alternative to the risky and expensive solution, which is hydrodesulfurization (HDS). The main part of this research is the study on (liquid + liquid) phase equilibria in {IL (1) + heptane, or thiophene, or 2-methylthiophene, or benzothiophene (2) binary systems and {IL (1) + thiophene/2-methylthiophene/benzothiophene (2) + heptane (3)} ternary system. In this work, five new synthesized tricyanomethanide – based ILs that is: N-(3-cyanopropyl)-N-methylmorpholinium tricyanomethanide, [Mo1,3CN][TCM], N-(3-hydroxypropyl)-N-methylmorpholinium tricyanomethanide, [Mo1,3OH][TCM], N-(3-cyanopropyl)pyridinium tricyanomethanide, [Py3CN][TCM], N-(3-hydroxypropyl)pyridinium tricyanomethanide, [Py3OH][TCM], N-(2-hydroxyethyl)pyridinium tricyanomethanide, [Py2OH][TCM] are analyzed as an extractant in desulfurization of model fuel. Based on the experimental ternary LLE data, the selectivity and solute distribution ratio are calculated and used to determine the efficiency of the tested ILs as solvents for the extraction of sulfur compounds from model fuel. The experimental results have been compared to literature data for other tricyanomethanide-based ILs and were discussed in terms of the selectivity and solute distribution ratio of separation of related systems. The NRTL equation was successfully used to correlate the LLE in binary systems as well as the experimental tie-lines.

Liquid–liquid equilibria of the ternary system (cyclopentanol + water + cyclopentyl formate) at (298.2–338.2) K: Measurements and correlation

Cyclopentanol is an important intermediate in a production of many chemical specialties. This paper relates to a development of a new technology of indirect cyclopentene hydration in the presence of formic acid and presents the data of liquid-liquid equilibrium (LLE) for the ternary system of (cyclopentanol + water + cyclopentyl formate) under atmospheric pressure and within a temperature range from 298.2 K to 338.2 K. The experiments were conducted in a temperature-controlled glass cell and the received data were correlated with nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) equations in order to obtain binary coefficients describing LLE of the given system. A consistency of the experimental tie-lines data was validated by the Bachman and Othmer-Tobias equations and the data fitting accuracy was evaluated by the use of the calculated average absolute deviation and the root-mean-square-error values. According to our best knowledge, the LLE of this system have not yet been published elsewhere and the values of binary interaction parameters should be used for the design of the reactor and separation units in the process of indirect cyclopentene hydration.

Synthesis, Characterization, and Antimicrobial Toxicity Study of Dicyanamide-Based Ionic Liquids and Their Application to Liquid–Liquid Extraction

Four different dicyanamide-based ionic liquids (ILs), [Cnmpy][DCA] (n = 4, 6, 8, and 10), were synthesized, characterized, and used to separate ethylbenzene from n-octane. Equilibrium data for the corresponding ternary systems were measured at 313.15 K under atmospheric pressure. A higher selectivity is observed for lower aromatic concentrations in the feed (20% max); this is a key factor in selecting a suitable IL. The distribution ratio and selectivity obtained in this work are comparable to those of commercial solvents. The nonrandom two-liquid model (NRTL) was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. Moreover, the antimicrobial activities of the ILs were evaluated by examining their 50% effective concentrations (EC50) using the standard microbroth dilution test against four human bacterial pathogens. 1-Butyl 3-methylpyridinium dicyanamide [C4mpy][DCA] was found as the most suitable IL among those investigated because of i...

Liquid–liquid equilibria of systems containing linseed oil biodiesel + methanol + glycerol: Experimental data and thermodynamic modeling

Biodiesel is known as a prominent candidate for the replacement of fossil-based fuels since the sources of these fuels have been depleted in the past few years. The most convenient process to produce biodiesel is the transesterification of triglycerides with an alcohol in the presence of a suitable catalyst. At the end of the reaction, two liquid phases comprised of biodiesel (main product), glycerol (by-product) and unreacted alcohol are co-exist. Phase equilibrium study is a tool to design the equipment that involved in the biodiesel production and purification processes. In this work, biodiesel was produced through the transesterification of linseed oil with methanol. Afterwards, the liquid–liquid equilibrium (LLE) data were measured for the ternary systems containing linseed oil biodiesel, methanol and glycerol at three different temperatures and atmospheric pressure. The binodal curves were determined by the cloud-point method in isothermal conditions. The adequacy of the experimental tie-lines has been confirmed using the Othmer–Tobias correlation. The results have been correlated using NRTL and UNIQUAC models. The binary interaction parameters of system components have been adjusted via an evolutionary algorithm so-called “BSOA” without and with closure equation. To predict the equilibrium composition, UNIFAC, UNIFAC-LLE, UNIFAC-DMD and UNIFAC-LBY models were used. Average deviations between the calculated and experimental data for NRTL, UNIQUAC, UNIFAC, UNIFAC-LLE, UNIFAC-DMD and UNIFAC-LBY were 1.574%, 1.380%, 3.187%, 3.164%, 3.881% and 3.960% respectively which show that UNIQUAC model represents the best correlation of experimental tie-lines. RMSD values have been improved by implementation of the closure equation.

Measurements and thermodynamic modelling of liquid–liquid equilibrium of PEG 6000–phosphate affinity aqueous two-phase systems at various ligand concentrations and pH

ABSTRACT The equilibrium behaviours of affinity two-phase liquid−liquid systems composed of polyethylene glycol (PEG) 6000 + phosphate salt + water were experimentally investigated at various pH values (4.5, 6, 7.5 and 8.4) and phosphate ligand mass fractions (PEG–PO4) (0%, 25%, 50%, 75%, 100%). The binodal curves were fitted to an empirical equation and the coefficients for the different pH and ligand concentration were estimated. The experimental tie-line compositions were estimated and correlated using the Othmer–Tobias and Bancroft equations, and the parameters were evaluated. The effects of the medium pH and the ligand amount on the phase behaviour were studied. It is found that the pH increasing and ligand concentration decreasing cause an expansion of the biphasic region. The liquid–liquid equilibrium experimental data obtained were well correlated to the activity coefficients of the non-random two-liquid (NRTL) model, and the mean deviations less than 0.68% between experimental and calculated mass fractions show that the NRTL activity model has a good ability to correlate the equilibrium compositions of the present system.

Separation of water/butan-1-ol with ionic liquids in ternary liquid-liquid phase equilibrium

In this work ionic liquids (ILs) as a novel popular solvents are proposed for removing butan-1-ol from the aqueous fermentation media. Ternary liquid-liquid phase equilibrium data are presented for mixtures of {ionic liquid (1) + butan-1-ol (2) + water (3)} at T = 328.15 K and ambient pressure. The ILs with long alkane chains such as hexadecyltrimethylammonium bis{(trifluomethyl)sulfonyl}imide, [N16,1,1,1][NTf2], 1,3-didecyl-2-methylimidazolium dicyanamide, [D2MIM][DCA] and tetrabutylphosphonium bis{(trifluomethyl)sulfonyl}imide, [P4,4,4,4][NTf2] have been tested. The results are discussed in terms of the selectivity and solute distribution ratio of separation of related systems. The complete miscibility in the binary liquid systems of butan-1-ol with three used ILs was observed. The ammonium-based IL in comparison with phosphonium-based IL shows lower selectivity and solute distribution ratio. The non-random two liquid NRTL model was used successfully to correlate the experimental tie-lines and to calculate the phase composition error in mole fraction in the ternary systems.

Isobaric Liquid–Liquid Equilibrium Measurements and Thermodynamics Modeling for Systems: Benzene + Cyclohexane + DESs at 303.15 and 323.15 K

In this work, three deep eutectic solvents (DESs), which are sulfolane + tetrabutylammonium bromide 3:1 (molar ratio, ST3:1), sulfolane + tetrabutylammonium bromide 7:1 (molar ratio, ST7:1), and ethylene glycol + trimethylamine hydrochloride 5:1 (molar ratio, ET5:1), were prepared and used as extractants for the separation of benzene and cyclohexane mixture by liquid–liquid extraction. Liquid–liquid equilibrium (LLE) data for the three ternary systems of benzene + cyclohexane + DESs were measured at 303.15 and 323.15 K under atmospheric pressure. The Othmer–Tobias equation was used to validate the consistency of the experimental tie-lines data and the regression coefficients R2 were all close to 1. Meanwhile, distribution coefficient (β), selectivity (S), and performance index (PI) were used to evaluate the performance of the three DESs, and the result indicates that the DESs ST3:1 and ST7:1 as extractants are more feasible for the separation of benzene and cyclohexane mixture compared to ET5:1. In additi...

ÊA simple approach for THE DETERMINATION AND CHARACTERIZATION OF TERNARY PHASE DIAGRAMS of aqueous two-phase systems composed of water, poly(ethylene) glycol and sodium carbonate

In this work, a simple experimental protocol to determine liquid-liquid phase diagrams of aqueous two-phase systems (ATPS) on a Chemical Engineering course is described. Throughout this laboratory set of experiments, the liquid-liquid ternary phase diagrams, tie-lines, tie-line lengths and critical points of ATPS will be determined. Ternary liquid-liquid phase diagrams composed of water, polyethylene glycol (PEG 200, 400 and 600 g·mol-1) and sodium carbonate (Na2CO3) were obtained by cloud-point titration method at room temperature. The respective tie-lines, tie-line lengths and critical points were also determined. Phase diagrams were represented both as conventional ternary phase diagrams and orthogonal phase diagrams. Through the analysis of the results obtained it was identified a higher ability to form ATPS with the increase of the polymer molecular weight. The interpretation of phase diagrams, particularly the most complex, the orthogonal ones, is not always easy to grasp by students, so this novel 3-hour-class educational approach could be potentially used to teach and help understanding 3-component liquid-liquid equilibrium and the formation of biphasic systems to undergraduate students, without requiring the use of volatile organic solvents.

Ammonium ionic liquids in separation of water/butan-1-ol using liquid-liquid equilibrium diagrams in ternary systems

In this work ionic liquids (ILs) as a novel popular solvents are proposed for removing butan-1-ol from the aqueous phase. Ternary liquid-liquid phase equilibrium data are presented for mixtures of {ionic liquid, IL (1) + butan-1-ol (2) + water (3)} at T = 328.15 K and pressure 101.3 kPa. The new synthesized by us ammonium-based ILs with long alkane chains, such as dimethyldodecylphenoxyethylammonium bis{(trifluoromethyl)sulfonyl}imide, [N1,1,12,2OPh][NTf2], dimethyldodecylphenoxyethylammonium dicyanamide, [N1,1,12,2OPh][DCA], benzyldimethyldodecylammonium bis{(trifluoromethyl)sulfonyl}imide, [N1,1,12,Bz][NTf2] and benzyldimethyldodecylammonium dicyanamide, [N1,1,12,Bz][DCA] have been tested. The selectivity and the solute distribution ratio of separation water/butan-1-ol were calculated and compared to the literature data. The complete solubility of butan-1-ol in the proposed ILs was observed at T = 328.15 K and pressure 101.3 kPa. The [N1,1,12,Bz][NTf2] is picked out as the most potential candidate as an extractant of butan-1-ol from water. The [N1,1,12,Bz][NTf2] shows only slightly lower selectivity than that observed in few phosphonium-based IL. The experimental tie-lines were successfully correlated with non-random two liquid NRTL model.

Separation of thiophene, or benzothiophene from model fuel using glycols. Liquid–liquid phase equilibria and oxidative desulfurization study

In this work the possibility of use glycols in extractive desulfurization will be discussed based on liquid–liquid phase equilibria (LLE) measurements for {glycol (1) + aromatic sulfur compound (2) + heptane (3)} ternary systems at T = 308.15 K and at pressure p = 0.1 MPa. Based on the experimental data, the performance of three glycols: diethylene glycol, triethylene glycol and polyethylene glycol (PEG 200) in the extraction of thiophene, or benzothiophene from heptane were determined. The selectivity, S, and solute distribution ratio, β derived from the experimental equilibrium data, were calculated and used to determine the efficiency of the tested glycols as a solvent for the extraction of sulfur compounds from model fuels. The NRTL equation was successfully used to correlate the experimental tie-lines and calculate the phase composition error in mole fraction in the ternary systems. The average root mean square deviation (RMSD) of the phase composition was less than 0.017. Additionally, the extractive desulfurization (EDS) of model fuels has been studied using diethylene glycol, triethylene glycol, polyethylene glycols (PEG 200), [BMIM][BF4] and eutectic mixtures of ([BMMOR][Br with diethylene glycol, or triethylene glycol). The oxidative extractions (ODS) were performed using different oxidative agents: the mixture of hydrogen peroxide with acetic acid, or formic acid, or benzoic acid, or iron (III) chloride and vanadium (V) oxide as well as the mixture of oxygen with N-hydroxyphthalimide (NHPI). Many parameters including the type of extractant and oxidizing agents, extraction time and temperature, as well as the ratio of the volume of model fuel to the volume of the extractant and number of extraction cycles on the extraction efficiency, were considered and discussed.

Liquid–liquid extraction of sulfur compounds from heptane with tricyanomethanide based ionic liquids

Liquid–liquid phase equilibrium (LLE) data for the {tricyanomethanide-based ionic liquid (1) + tiophene, or benzothiophene (2) + heptane (3)} ternary systems were experimentally determined at T = 308.15 K and at pressure p = 0.1 MPa. In this work three ILs, that is: 1-butyl-1-methylmorpholinium tricyanomethanide, [BMMOR][TCM], 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM] and 1-hexyl-1-methylmorpholinium tricyanomethanide, [HMMOR][TCM] have been investigated. The high solubility of sulfur compounds and practically complete immiscibility of heptane with the tested ionic liquids have been observed. The selectivity, S12 and solute distribution ratio, k12 derived from the experimental equilibrium data, were calculated and used to determine the efficiency of these ionic liquids as solvents for the extraction of sulfur compounds from model fuels. The experimental results have been compared to literature data for other tricyanomethanide-based ILs and were discussed in terms of the selectivity and solute distribution ratio of separation of related systems. The NRTL equation was successfully used to correlate the experimental tie-lines. The average root mean square (RMSD) of the phase composition was less than 0.8%. Additionally, the oxidative-extractive desulfurization of model fuels has been studied using tricyanomethanide-based ionic liquid (IL): [BMMOR][TCM] and [BMPYR][TCM] and deep eutectic solvent (DES): ([BMMOR] [Br] + diethylene glycol). Model liquid fuel was prepared by dissolving benzothiophene in octane, 500 ppm of sulfur. Oxidation was achieved by adding hydrogen peroxide and acetic acid to the mixture. Different parameters such as a type of extractant, extraction time, and oxidant to sulfur molar ratio and temperature were optimized. The addition of oxidizing agent improves the efficiency of sulfur extraction and the highest extraction efficiency, equal to 69.1%, was obtained for [BMMOR][TCM] at T = 318.15 K.

Thermodynamic study of aqueous two-phase systems containing biocompatible cholinium aminoate ionic-liquids and polyethylene glycol di-methyl ether 250 and their performances for bovine serum albumin separation

Aqueous two-phase systems, ATPSs, are known as an interesting media for the separation and purification of vital biomolecules in biotechnology applications. From this viewpoint, the ambition of this work is investigating ability of cholinium aminoate ([Ch][AA]) as novel, low toxic and high biodegradable ionic liquids, including of cholinium glycinate ([Ch][Gly]), cholinium prolinate ([Ch][l-Pro]) and cholinium valinate ([Ch][l-Val]) for inducing ATPSs with polyethylene glycol di-methyl ether 250, PEGDME250, and then evaluating their performances for partitioning of bovine serum albumin, BSA, as a model protein. For achieving this purpose, binodal curves and tie-lines were experimentally measured at T = (298.15, 308.15 and 318.15) K under atmospheric pressure (≈85 kPa) for all of the aforementioned systems. The influences of ionic liquid anion and temperature were searched systematically on the binodal curve and tie-lines. The phase splitting ability in these systems was assessed by utilizing the effective exclude volume theory from which the locations of binodals may be predicted and the Setschenow-type equation which provides salting-out coefficients by fitting the experimental tie-lines to this equation. Two empirical equations including of Merchuk equation were applied in order to represent the binodal data. Moreover, the Othmer-Tobias and Bancraft, Osmotic virial equations and two versions of NRTL models (m- or e-NRTL) were selected to correlate the tie-lines. In addition, the partition behaviour of BSA was studied by measuring of partition coefficient and extraction efficiency in the mentioned systems. The measured partition coefficients for BSA were discussed on the basis of physiochemical properties of amino acids involved in ionic liquid structure.

Experimental and correlational study of phase equilibria in aqueous solutions of phosphoric acid with alcohols at different temperatures

Liquid-liquid equilibrium (LLE) data were measured for the aqueous mixtures of phosphoric acid with 1-pentanol and 1-heptanol at T=(298.2, 308.2, and 318.2) K and atmospheric pressure. These ternary systems exhibit as Treybal's type-1 liquid-liquid phase behavior. The reliability of the experimental tie-lines was checked using the Othmer-Tobias and Hand correlation equations. The activity coefficient models of NRTL and UNIQUAC were applied to fit the experimental tie lines. For these models, values of the binary interaction parameters between each pair of components in the studied systems were obtained. Experimental distribution coefficients and selectivity factors for the immiscibility regions were determined.