Bancroft Equations Research Articles

Design of novel aqueous two-phase systems to be coupled in biological remediation processes

The ability of a biodegradable Deep Eutectic Solvent (DES) reline to induce phase segregation in aqueous solutions of polymeric non-ionic surfactants (Tween 20 and Tween 80) has been demonstrated as a preliminary step to be employed for assisting a biological degradation process of a model contaminant. The binodal curves for systems composed of (surfactants + reline + Water) have been determined at several temperatures, and the experimental data have been correlated using well-known equations. The equilibrium data have been analysed in the light of the operating temperature and the hydrophobicity of surfactants. Tie-lines of these systems have been determined, together with useful parameters such as tie-line length and tie-line slopes. Othmer-Tobias and Bancroft equations have been applied to provide an adequate description of the equilibrium data. Finally, the application of this new approach for the remediation of aqueous polluted effluent has proven to be highly efficient, with extraction percentages exceeding 99% for two model persistent contaminants (Acid Black 48 and Crystal Violet). Consequently, this ATPS is proposed as an extra-stage to enhance the remediation percentages achieved through biological methods. Furthermore, the process has been simulated using commercial software.

Improving the Extraction of Tetracycline from Aqueous Solution by the Use of Acetone as an Adjuvant in ATPS Containing Poly(ethylene glycol) and Organic Salts and the Study of Its Phase Behavior

In this study, the solubility data of two-phase systems for tripotassium citrate and potassium sodium tartrate with PEG4000, 3000, 2000, 1000, and 400 g/mol were experimentally obtained. These data were fitted using empirical equations with MATLAB software. Also, the tie-lines were obtained and fitted by the Othmer–Tobias and Bancroft equations. The results were confirmed by UNIQUAC modeling. Tripotassium citrate resulted as the best salt according to the salting-out ability. The 16 experiments were done based on the Taguchi design of experiment (DOE) to extract the tetracycline from an aqueous solution; the results were analyzed with Minitab 18 software. Acetone was used as an adjuvant in this process. Polymer molecular weight and acetone concentration had the greatest effects on tetracycline extraction efficiency. The maximum extraction (99.78%) was obtained at the concentration of 5 ppm of tetracycline and 8 (% w/w) of acetone with PEG400.

Performance of Organic Salts as Salting-Out Media on Recovering Nicotine from Water

Three degradable organic salts, sodium formate (NaCHO2), sodium succinate (Na2C4H4O4), and sodium citrate (Na3C6H5O7), were evaluated for the extraction of nicotine from aqueous solutions by forming two-phase systems. The detailed phase diagrams, including the binodal curves and tie-lines, were experimentally determined at 298.15 K and atmospheric pressure by the cloud point method. The three empirical equations including Merchuk, Pirdashti, and Hu models gave a perfect correlation of the experimental binodal data, and the reliability of liquid–liquid equilibrium data was evaluated using the Othmer–Tobias and Bancroft equations. It could be found that all adopted organic salts promoted the expansion of two-phase regions and had a high partition yield for nicotine extraction from water. The relative tendency of the anions to form aqueous two-phase systems being C6H5O73– > C4H4O42– > CHO2– was consistent with their valence order, which could be explained by the Gibbs hydration free-energy theory. Furthermore, the salting-out ability of salt anions was also in accordance with the parameter order (Na3C6H5O7 > Na2C4H4O4 > NaCHO2) of the calculated effective excluded volume. Increasing the temperature from 298.15 to 318.15 K and the pH value from 8.0 to 11.0 at 298.15 K was conducive to the two-phase formation of the ternary nicotine + Na3C6H5O7 + water system to increase the distribution coefficients and recovery percentages of nicotine. Computational thermodynamics of cloud point indicated that the more negative Gibbs free energy with temperature promoted the desolvation of nicotine to migrate preferentially to the top phase. It was concluded that degradable organic salts would be effective for nicotine extraction at an industrial scale.

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.

Salting-Out-Assisted Liquid–Liquid Extraction for Nicotine from Its Aqueous Solutions

The complete effectiveness of various inorganic salts (NaCl, KCl, NaBr, KBr, Na2CO3, and Na2SO4) to form two-phase systems was systematically evaluated for separating nicotine from its aqueous solutions. The binodal curve and tie lines for nicotine + salt + water ternary systems were experimentally determined at 298.15 K and atmospheric pressure. The salting-out effectiveness was accounted for by phase diagrams, as well as partition coefficients and recovery percentages of nicotine. The binodal curves obtained experimentally were successfully fitted to the Merchuk model, and the reliability of tie-line data was evaluated using the Othmer–Tobias and Bancroft equations. The results clearly show that all investigated salts, as salting-out media, cause the expansion of the two-phase region and have high partition yield for the separation of nicotine from its aqueous solutions. It is also observed that both cations and anions present an influence on the liquid–liquid equilibrium. The relative tendency of anions to form two-phase systems, CO32– > SO42– > Cl– > Br–, follows the position of anions in the Hofmeister series. Due to the stronger interaction of Na+ with the nicotine nitrogen than K+, the effectiveness order of cations (K+ > Na+) follows the opposite trend with the Hofmeister series. Furthermore, the order Na2CO3 > Na2SO4 > KCl > NaCl > KBr > NaBr for the effective excluded volume (EEV) of different salts is consistent with the size order of the heterogeneous region. Thus, EEV can be used as a predictive tool for the biphase-forming ability of salts. The partition coefficients and recovery percentages of nicotine are found to increase with the increase of temperature and pH. The calculated entropy of the cloud point indicates that the high positive entropy is the driving force for the two-phase formation.

Phase Equilibria of PEG/Sulfate Salt Aqueous Two-Phase Systems: Effects of pH and Molecular Weight of Polymer

In this study, the liquid-liquid equilibrium (LLE) in the aqueous two-phase system (ATPS) formed by polyethylene glycol (PEG1500 and PEG6000) and magnesium sulfate is investigated. The experimental measurements were performed at temperature of 298.15 K and pH values of 3.60, 5.00, 6.67. Densities and refractive indices of the mixtures were first measured to obtain the compositions from the plotted tie lines. The effects of pH and molecular mass of polymers on the binodal curve, tie lines length (TLL) and slope of tie line (STL) have been examined. It was found the pH values and molecular weight rise the heterogeneous region for each system. The binodal curve was fitted to the Merchuk and the Pirdashti equations. The Othmer-Tobias as well as the Bancroft equations were subsequently selected to correlate the compositions of the tie lines at equilibrium where the fitted parameters are derived. In addition, the Guan’s equation was utilized to correlate the experimental binodal curves. Finally, the effectively excluded volume (EEV) was determined and the values were found to increase with pH.

Lycopene partition in new aqueous two-phase systems

The present work aimed to characterize new aqueous two-phase systems (ATPS) formed by polyvinylpyrrolidone 10000 g·mol−1 (PVP10K) + Na2SO4 + H2O, PVP10K + ZnSO4 + H2O and PVP10K + Na2C4H4O6 + H2O at 278.15, 288.15, and 298.15 K as well as several pH values that were used to evaluate the lycopene partition. For all systems, variations in temperature and pH did not significantly influence the biphasic region. As for the influence of cations and anions in the phase segregation process, there was no significant difference between anions SO42− and C4H4O62−. Relative to cations, Zn2+ showed a greater capacity to induce phase separation than Na+. However, due to the greater number of electrically charged species per mole of Na2SO4 relative to ZnSO4, the sodium sulfate demonstrated greater efficiency in the phase separation process. The data were adjusted with good correlation using the Merchuk equation for the binodal curves and Othmer-Tobias and Bancroft equations for tie lines. These ATPS were applied to the lycopene partition, with the solute preferentially partitioned to the top phase (3.98 ± 0.09 < K < 23.6 ± 0.3), and the increase in TLL values and temperature caused an increase in the partition coefficient, indicating that the process is directed enthalpically. Thus, these ATPS proved to be an excellent environmentally safe alternative for application in the extraction of lycopene.

Influence of the Molecular Weight of Polymer on the Poly Vinyl Pyrrolidone and Zinc Sulfate Phase Diagram of Aqueous Two-Phase Systems

The study obtained the Liquid – Liquid Equilibrium (LLE) for Aqueous Two-Phase Systems (ATPSs) containing poly (vinyl pyrrolidone) (PVP) (10000, 24000, and 40000) and zinc sulfate at 298.15 K. The phase area is expanded according to the increased molecular weight of the polymer. Density and refractive indices were employed as the physical properties for obtaining phase composition and end of tie-line evaluations. The effect of molecular weight is discussed in relation to binodal curve, Tie-Line Length (TLL), and Slope of Tie Line (STL) determinations. Following the increase in polymer molecular weight value, the TLL increased and STL slightly decreased. Accordingly, Pirdashti’s equation was used to correlate binodal curve evaluations of these systems. Furthermore, tie-line data points were correlated by Othmer-Tobias, Hand, and Bancroft equations. Finally, the study determined the Effective Excluded Volume (EEV) of salt into the PVP aqueous solution.

The phase behavior of n-ethylpyridinium tetrafluoroborate and sodium-based salts ATPS and its application in 2-chlorophenol extraction

In this paper, the aqueous two-phase systems (ATPS) containing n -ethylpyridinium tetrafluoroborate ([EPy]BF 4 ), sodium-based salts, and water were studied and the extraction efficiency of 2-chlorophenol was measured to study the ATPS performance in extracting phenolic compounds. The binodal curves of [EPy]BF 4 + sodium carbonate (Na 2 CO 3 ) ATPS and [EPy]BF 4 + sodium dihydrogen phosphate (NaH 2 PO 4 ) ATPS have been determined at 308.15 K, 318.15 K, and 328.15 K and atmospheric pressure. After getting good correlation with Merchuk equation, the binodal curves together with gravimetric method were used to calculate the tie-lines data. Furthermore, the reliability of tie-lines data was verified using Othmer-Tobias and Bancroft equations. Then, the salt influence and temperature influence on the phase behavior were discussed and the results show the salt-outing ability of Na 2 CO 3 is better than NaH 2 PO 4 . With the aim of studying the ATPS performance in extracting phenolic compounds, extraction efficiency for 2-chlorophenol at different temperatures were studied and the results show that [EPy]BF 4 + Na 2 CO 3 ATPS is preferred than [EPy]BF 4 + NaH 2 PO 4 ATPS in applications.

Novel ethyl lactate based ATPS for the purification of rutin and quercetin

The application of new aqueous two-phase systems (ATPS) composed by a hydrophilic green solvent, ethyl lactate, and two low environmental impact salts: sodium and potassium citrate have been studied for the recovery of two flavonoids from aqueous solutions. First, to understand the phase formation process of the ATPS, binodal curves and tie-lines and their respective slopes and tie-line lengths were determined at T = 298.15 K and atmospheric pressure. The degree of consistency of the tie-lines was evaluated using Othmer-Tobias and Bancroft equations. Moreover, the influence of the change of the salt cation on the phase behaviour has been assessed. Furthermore, the UNIversal QUAsiChemical (UNIQUAC) thermodynamic model was applied to describe the phase equilibria presented in this work. Furthermore, the partitioning of two flavonoids, rutin and quercetin, in these ATPS {ethyl lactate (1) + citrate salts (2) + water (3)} was measured at T = 298.15 K and atmospheric pressure. Finally, the obtained results were compared with those found in literature.

The effect of temperature on phase equilibria of polyethylene glycol (PEG8000)-K2SO4-H2O at T = (288.15, 298.15, 308.15) K

The phase behavior of potassium sulfate (K 2 SO 4 ) in polyethylene glycol with molecular weight 8000 (PEG8000) and water (H 2 O) mixed solvent at 288.15, 298.15, and 308.15 K were determined. According to the results, when the temperature are 288.15 and 298.15 K, there is only a solid–liquid phase equilibrium relationship in the system, and the phase diagrams are both divided into three parts which respectively are the regions of unsaturated homogeneous liquid (L), one liquid and one solid K 2 SO 4 (L + S) and one liquid and two solids K 2 SO 4 and PEG8000 (L + 2S). The solubility of K 2 SO 4 in PEG8000-H 2 O mixed solvent decreased with the addition of the PEG8000 in the solution. Comparing the diagrams of 288.15 and 298.15 K, the sizes of regions of (L) and (L + S) increased and that of (L + 2S) decreased with the increase of temperature. While at 308.15 K, solid–liquid and liquid–liquid equilibrium coexist, and there are six parts in the complete phase diagram at 308.15 K, adding the areas of one liquid and one solid K 2 SO 4 (L + S), two liquids (2 L), two liquids and one solid K 2 SO 4 (2 L + S). The equations developed by Merchuk, Hu, and Jayapal were used to fit the binodal curves data of the system at 308.15 K, meanwhile, the experimental tie-line data of the system at 308.15 K were correlated by Othmer-Tobias equation and Bancroft equation.

Aqueous two-phase systems formed by different phase-forming components: Equilibrium diagrams and dye partitioning study

The present work aimed to characterize new aqueous two-phase system (ATPS) formed by Triton X-100 + Li2SO4 + H2O, polyvinylpyrrolidone Mw = 10,000 g mol−1 (PVP10k) + Li2SO4 + H2O, and Triton X-100 + PVP10k + H2O, evaluating the effect of temperature and the nature of ATPS-forming components on the biphasic region. ATPSs formed by Li2SO4 showed greater efficiency in phase segregation compared to ATPSs formed by polymer/surfactant, with the biphasic area of ATPSs formed by Triton X-100 greater than that formed by PVP10k. For all ATPSs studied, temperature had a small effect on the biphasic region. The data were fitted with good correlation using the Merchuk equation for the binodal curves and Othmer–Tobias and Bancroft equations for the tie-lines. The partitioning studies show that there is an uneven distribution of Reactive Yellow HE-4R dye between the phases for all ATPSs and, with a tie-line length increase, there is an increase in the tendency of the dye to partition to the phase in which it interacts most strongly. For ATPSs formed by Li2SO4, the dye is preferentially transferred to the macromolecule-rich phase (top phase), whereas for the system formed by polymer/surfactant, the dye is partitioned to the PVP10k enriched phase (bottom phase).

Phase equilibria measurements and correlation of aqueous solvent of PEG4000 with rubidium chloride at (288.15, 298.15, and 308.15) K

The phase equilibria of ternary system polyethylene glycol with molar mass of 4000 g∙mol−1(PEG 4000), rubidium chloride (RbCl) and water (H2O) were determined at T=(288.15, 298.15, 308.15) K. Results show that there is only solid-liquid equilibrium (SLE) relationship in the system at 288.15 K, both of solid-liquid equilibrium (SLE) and liquid-liquid equilibrium (LLE) are found in the system at 298.15 K and 308.15 K. The phase diagram at 288.15 K was divided into 3 areas including the region L (unsaturated liquid phase), the region L + S (saturated solutions with a solid phase RbCl) and the region L + 2S (saturated liquid phase with two solid phases of PEG4000 and RbCl) and the solubility of RbCl decreased with PEG4000 increasing. The complete phase diagrams at 298.15 K and 308.15 K including 6 areas (L (unsaturated liquid phase), 2L (aqueous two-phase), L + 2S (saturated liquid phase with two solid phases of PEG4000 and RbCl), 2L + S (two liquids with one solid phase RbCl), and 2 areas of L + S (saturated solutions with one solid phase RbCl) were constructed. Furthermore, the binodal curves, compositions, length of the tie-line (TLL) and slope of tie-line (STL) were obtained for these mixed solvent systems at 298.15 K and 308.15 K. Three nonlinear expressions, proposed by Mistry, Hu, and Jayapal, were used to fit the binodal curves. The data of tie-line were correlated by using Othmer-Tobias equations, Bancroft equations, Hand equation, Bachman equations and the Chen-NRTL model. All the presented results, both the experimental and calculated data, show convincing values.

Towards the use of eco-friendly solvents as adjuvants in remediation processes

Abstract The growing social concern regarding the use of more environmentally friendly processes is compelling the search of more biocompatible solvents able to overcome the drawbacks associated to the conventional ones. Thus, in this work, a Deep Eutectic Solvent (cholinium chloride:urea) was demonstrated to act as salting out agent in aqueous solutions of a model non-ionic surfactant (Triton X-100). Thus, the immiscibility region was thoroughly mapped in a range of temperatures, from T 293.15 to 323.15 K. The experimental data for each solubility curves were fitted to different empirical models based on exponential and polynomial equations. Furthermore, Othmer-Tobias and Bancroft equations have been used to correlate the tie-line data, and to provide a clearer picture of the role of these solvents as phase promoters in surfactants solutions. Finally, the extraction capacity of this system at 303.15 K was assessed for removing textiles dyes from aqueous streams, in order to demonstrate the suitability of DESs to be used as adjuvants in the remediation of industrial effluents.

Phase behavior of tetramethylurea + MCl (M = Na, K, Rb, Cs) + H2O systems at 288.2, 298.2 and 308.2 K

For this article, we investigated the phase behavior and physicochemical properties of the ternary systems MCl (M = Na, K, Rb, Cs) + tetramethylurea (TMU) + H2O at temperatures of 288.2, 298.2 and 308.2 K. For (solid–liquid) equilibrium (SLE) systems (NaCl/KCl/RbCl + TMU + H2O at three temperatures and CsCl + TMU + H2O at 288.2 K), the density, solubility and refractive index about the saturated solutions was obtained. About (liquid–liquid) equilibrium (LLE) systems (CsCl + TMU + H2O at 298.2 and 308.2 K), the binodal curves and tie lines were obtained. The three parameter equation, Othmer-Tobias and Bancroft equations were used to correlate the SLE and LLE data.

Phase equilibrium and partitioning of cephalosporins (cephalexin, cefazolin, cefixime) in aqueous two-phase systems based on carbohydrates (glucose, fructose, sucrose, maltose) / acetonitrile

In recent decades, the use of aqueous two-phase system (ATPS) for bio-separation engineering has attracted increasing interest. In this work, ATPSs based on carbohydrates and acetonitrile were used to explore the partitioning behavior of cephalosporin antibiotics including cephalexin, cefazolin, and cefixime. For this purpose, four ATPSs containing acetonitrile and glucose, fructose, sucrose, and maltose have been studied. Initially, the phase diagrams were acquired at 300 K and then correlated by the Merchuk equation. The results showed that the ATPS composed of disaccharides have a broader two-phase region than monosaccharides. Furthermore, for the studied systems, tie-lines were obtained and their accuracy was examined by Othmer-Tobias and Bancroft equations. Moreover, tie-lines length and slope of tie-lines were determined. Besides, the partition coefficient of cephalosporins in four different ATPSs and a total of 48 tie-lines were investigated. Based on the results, it can be concluded that by increasing the concentration of carbohydrates, the partition coefficient increases. The maximum partitioning coefficient of cephalexin and cefazolin were obtained to be 19.2 and 17, respectively, with a recovery yield of 93% in the carbohydrate phase, which corresponds to the system (16 wt % glucose + 50 wt % acetonitrile + water). While the highest partitioning coefficient of cefixime was 6.4, with a recovery percentage of 81% for the system (16 wt % sucrose + 50 wt % acetonitrile + water). The results of this work indicate that these systems have a potential for separation and recovery of the understudied antibiotics.

The temperature influence on the phase behavior of ionic liquid based aqueous two-phase systems and its extraction efficiency of 2-chlorophenol

With the increasing research on the aqueous two-phase systems (ATPS), the ATPS containing ionic liquid (IL) and salt have been widely used in the extraction and purification process. In this work, the partitioning of 2-chlorophenol in novel ATPS composed of n-butylpyridinium trifluoromethanesulfonate and salts (ammonium sulfate, sodium dihydrogen phosphate) is evaluated. Firstly, the cloud point titration method was used to determine the binodal curves data experimentally at four temperatures and atmospheric pressure. And Merchuk equation was used to fit the binodal curves. Then, the gravimetric method was used to initially determine the tie-lines data and the concentration of all the ions in the top and bottom phases were determined by ion chromatography method to study the ion exchange in the ATPS. The reliability of tie-lines was evaluated by Othmer-Tobias and Bancroft equations. Finally, the influence of types of salts and temperature on the phase diagrams were studied carefully. Besides, in order to analyze the application of ATPS in the extraction, the partition coefficient of 2-chlorophenol was calculated at the same total composition while at different temperature. The ATPS formed by n-butylpyridinium trifluoromethanesulfonate, ammonium sulfate, and water at 298.15 K was found to have the maximum amount of partition coefficient and extraction efficiency.

Separation of erythromycin using aqueous two-phase system based on acetonitrile and carbohydrates

In this work, the ability of aqueous two-phase system (ATPS) based on carbohydrates (sorbitol, maltose monohydrate, and fructose) and acetonitrile for separation of erythromycin was investigated. For this purpose, binodal curves and tie-lines for three ATPSs were determined. The LLE data was also successfully correlated with the Othmer-Tobias and the Bancroft equations. The effective excluded volume (EEV) model was used to estimate the soluting-out ability of carbohydrates. Moreover, the partitioning of erythromycin in the ATPS was studied. Furthermore, the effect of carbohydrate and acetonitrile concentrations as well as temperature on the partitioning behavior of erythromycin were examined. In order to estimate the effect of temperature on the partitioning of erythromycin, molar Gibbs energy (ΔGEA), molar entropy (ΔSEA), and molar enthalpy (ΔHEA) were calculated. In all ATPSs the top phase is acetonitrile-rich while the bottom phase is carbohydrate-rich and erythromycin tends to migrate to the top phase. The results show that sorbitol has a higher soluting-out ability than maltose monohydrate and fructose. In addition, it can be concluded that the partitioning process of erythromycin is exothermic and the partition coefficient was decreased with increasing of erythromycin content.

Phase behavior for 1-butyl-3-methylimidazolium tetrafluoroborate with sodium oxalate/succinate/formate aqueous two-phase systems at 298.15 and 308.15 K

The liquid––liquid equilibrium (LLE) data and phase composition of the aqueous 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) + sodium oxalate (Na2C2O4), [Bmim]BF4 + sodium succinate (Na2C4H4O4) and [Bmim]BF4 + sodium formate (NaHCOO) mixtures have been measured at 298.15 and 308.15 K. The effect of salts and temperature on binodal curves were studied in this work and a significant relationship has been observed between the salting-out ability and the Gibbs energy of hydration of the ions. The binodal data obtained were correlated by the Pirdashti and Merchuk equations and the tie-line compositions were well-fitted by the Othmer-Tobias and Bancroft equations and the experimental tie-line data were well correlated with extended UNIQUAC model. Additionally, the effective excluded volume values were also determined to analyze the salting-out abilities of the three salts which follow the order of Na2C2O4 > Na2C4H4O4 > NaHCOO.

Liquid–Liquid Equilibrium of Imidazolium Ionic Liquids + Phosphate + Water Aqueous Two-Phase Systems and Correlation

Binodal curves of the aqueous 1-butyl-3-methylimidazolium tetrafluoroborate([C4mim]BF4) + kosmotropic salt (Na3PO4,(NH4)3PO4) + water aqueous two-phase systems were determined experimentally at 288.15, 298.15, 308.15 and 318.15 K. Three empirical equations were used to correlate the binodal data. All three empirical equations reproduce the data with a high degree of precision. The effect of temperature on the binodal curves was studied. Corresponding to two different salts, the two-phase area decreases with increasing temperature. From the binodal model for these systems, the effective excluded volumes (EEV) were obtained. The binodal curves and EEV both indicate that the salting-out abilities are in the order: Na3PO4 > (NH4)3PO4. And, the reliability of the tie-line compositions was proved by the empirical correlation with the Othmer–Tobias and Bancroft equations. The results show that the salting-out strength is greater at lower temperatures. Additionally, a relatively simple two-parameter equation was used for the correlation of the tie-line data.