(Surfactant + polymer) interaction parameter studied by (liquid + liquid) equilibrium data of quaternary aqueous solution containing surfactant,polymer, and salt

(Liquid + liquid) equilibrium (LLE) data of quaternary aqueous system containing polyoxyethylene (20) cetyl ether (with abbreviation name Brij 58, non-ionic surfactant), diammonium hydrogen phosphate, and poly ethylene glycol (PEG) with three molar masses {M_W = (1000, 6000, and 35,000) g · mol^?1} have been determined experimentally at T = 313.15 K.Furthermore, the Flory–Huggins theory with two electrostatic terms (Debye–Hückel and Pitzer–Debye–Hückel equations) have been used to calculate the phase behavior of the quaternary systems and (surfactant + polymer) interaction parameter as well as interaction parameters between other species. Temperature dependency of the parameters of the Flory–Huggins theory has been obtained.Also an effort have been done to show that addition of PEG as well as increasing the temperature can shift the binodal curves of the ternary aqueous system containing surfactant and salt to lower mole fraction of salt. Also the effect of polymer molar mass on the binodal diagram displacement has been discussed.     

Quaternary (liquid + liquid) equilibria of aqueous two-phase poly (ethylene glycol), poly (DMAM–TBAM), and KH2PO4: Experimental and generalized Flory–Huggins theory

Quaternary (liquid + liquid) equilibrium (LLE) data of the aqueous two-phase poly (ethylene glycol), poly (N,N-dimethylacrylamide-t-butylacrylamide) with abbreviation name poly (DMAM–TBAM) as a hydrophobic association water-soluble copolymer and KH₂PO₄ has been determined experimentally at T = 338.15 K. Furthermore, the generalized Flory–Huggins theory with two electrostatic terms (the Debye–Hückel and Pitzer–Debye–Hückel) was used for correlation of the phase behavior of the quaternary system and the interaction parameters between all species were calculated.It was found that addition of poly (DMAM–TBAM) copolymer as well as changing the temperature can shift the binodal curves of aqueous two-phase systems containing polyethylene glycol (PEG) and salt. Also, the phase behavior of the DMAM–TBAM copolymer with some salts containing sodium chloride, ammonium hydrogen phosphate, potassium hydrogen phosphate, and sodium carbonate were studied experimentally at T = 338.15 K and the effect of the salt type on the their binodal curves was determined.     

(Liquid + liquid) and (liquid + solid) equilibrium of aqueous two-phase systems containing poly ethylene glycol di-methyl ether 2000 and di-sodium hydrogen phosphate

(Liquid + liquid) equilibrium (LLE) for the {poly ethylene glycol di-methyl ether 2000 (PEGDME₂₀₀₀) + Na₂HPO₄ + H₂O} system have been determined experimentally at T = (298.15, 308.15, 313.15, and 318.15) K. The effects of temperature on the binodals and tie-lines for the investigated aqueous two-phase system (ATPS) have been studied. An empirical non-linear expression developed by Merchuk was used for reproducing the experimental binodal data. In this work, the three fitting parameters of the Merchuk equation were obtained with the temperature dependence expressed in the linear form with (T ? T₀) K as a variable. Furthermore, the modified local composition segment-based NRTL and Wilson models and also osmotic virial equation were used to describe the LLE data of the studied system. Also, the effects of the type of salt on LLE are discussed. In addition, the effects of end groups of the polymers PEGDME₂₀₀₀ and poly ethylene glycol 2000 on phase forming ability were studied. The complete phase diagram for the poly ethylene {glycol di-methyl ether 2000 (PEGDME₂₀₀₀) + Na₂HPO₄ + H₂O} system has also been determined at T = 298.15 K.     

(Liquid + liquid) equilibrium of (NaNO3 + PEG 4000 + H2O) ternary system at different temperatures

Phase diagram and (liquid + liquid) equilibrium (LLE) data for the (NaNO₃ + polyethylene glycol 4000 (PEG 4000) + H₂O) system have been determined experimentally at T = (288.15 and 308.15) K. The effects of temperature on the binodal curves and tie-lines have been studied and it was found that an increasing in temperature caused the expansion of two-phase region. The Chen-NRTL, modified Wilson and UNIQUAC models were used to correlate the experimental tie-line data. The results show that the quality of fitting is better with the UNIQUAC model.     

A thermodynamic study on solubility and liquid−liquid phase behaviour for 2,2,2-trifluoroethanol + cyclohexane + 1-butanol at three temperatures and pressure 101.3 kPa

This study demonstrates the course of solubility and (liquid + liquid) equilibrium (LLE) for the system (cyclohexane + 1-butanol + 2,2,2-trifluoroethanol) at temperatures of (288.15, 298.15, and 308.15) K and pressure 101.3 kPa. The titration method was used to assess solubility (binodal) curves, while a direct analytical method to acquire tie lines.The consistency of the binodal curves and phase diagrams data were well calculated by Hand and Othmer–Tobias empirical equations. The NRTL and UNIQUAC thermodynamic models gave accurate tie-line values for the systems. Plait-point, distribution coefficient, solvent selectivity, and NRTL and UNIQUAC binary interaction parameters were obtained.The immiscibility region of the system decreases significantly with increasing temperature. The results present an overview of the high efficiency of liquid extraction using 2,2,2-trifluoroethanol as solvent to yield pure cyclohexane from its 1-butanol azeotrope mixture at ambient temperatures.     

Influence of temperature on the (liquid + liquid) equilibria of {3-methyl pentane + cyclopentane + methanol} ternary system at T = (293.15, 297.15, and 299.15) K

In order to show the influence of temperature on the (liquid + liquid) equilibria (LLE) of the {3-methyl pentane (1) + cyclopentane (2) + methanol (3)} ternary system, equilibrium results at T = (293.15, 297.15, and 299.15) K are reported. The effect of the temperature on the (liquid + liquid) equilibrium is determined and discussed. Experimental results show that this ternary system is completely homogeneous beyond T = 300 K. All chemicals were quantified by gas chromatography using a thermal conductivity detector. The tie line results were satisfactorily correlated by the Othmer and Tobias method, and the plait point coordinates for the three temperatures were estimated. Experimental values for the ternary system are compared with values calculated by the NRTL and UNIQUAC equations, and predicted by means of the UNIFAC group contribution method. It is found that the UNIQUAC and NRTL models provide similar good correlations of the solubility curve at these three temperatures. Finally, the UNIFAC model predicts binodal band type curves in the range of temperatures studied here, similar to those observed for systems classified by Treybal as type 2, instead of type 1 as experimentally observed. Distribution coefficients were also analysed through distribution curves.     

(Liquid + liquid) equilibria of (water + butyric acid + esters) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {water (1) + butyric acid (2) + ethyl propionate or dimethyl phthalate or dibutyl phthalate (3)} at T = 298.15 K and (101.3 ± 0.7) kPa. The relative mutual solubility of the butyric acid is higher in the layers of esters than in the aqueous layer. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of (water + butyric acid + dibasic esters) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {water (1) + butyric acid (2) + dimethyl succinate or dimethyl glutarate or dimethyl adipate (3)} at T = 298.15 K and p = (101.3 ± 0.7) kPa. The relative mutual solubility of the butyric acid is higher in the dibasic esters layers than in the aqueous layer. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of (water + propionic acid + diethyl succinate or diethyl glutarate or diethyl adipate) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for {water (1) + propionic acid (2) + diethyl succinate or diethyl glutarate or diethyl adipate (3)} at T = 298.15 K and 101.3 ± 0.7 kPa. The relative mutual solubility of the propionic acid is higher in the dibasic esters layers than in the aqueous layers. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems was predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of (water + lactic acid + alcohol) ternary systems

(Liquid + liquid) equilibrium (LLE) measurements of the solubility (binodal) curves and tie-line end compositions were carried out for {water (1) + lactic acid (2) + octanol, or nonanol, or decanol (3)} at T = 298.15 K and 101.3 ± 0.7 kPa. The relative mutual solubility of lactic acid is higher in the water layers than in the organic layers. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE results for the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Separation of benzene from alkanes by solvent extraction with 1-ethylpyridinium ethylsulfate ionic liquid

The (liquid + liquid) equilibrium (LLE) data for ternary mixtures {alkane + benzene + 1-ethylpyridinium ethylsulfate ([EPy][EtSO₄])} at T = (283.15 and 298.15) K and atmospheric pressure are presented. The alkanes used were hexane and heptane. The cloud point method was used to determinate the binodal curve, and the tie-line compositions were obtained by density measurements. The LLE data obtained were used to calculate distribution coefficients and selectivity values. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations. Correlation of the experimental tie-lines was conducted through the use of NRTL equation, which provides good correlation of the experimental data.The results show that [EPy][EtSO₄] can be used as an alternative solvent in liquid extraction processes for the removal of benzene from its mixtures with alkanes.     

Quaternary (liquid + liquid) equilibria of aqueous two-phase polyethylene glycol,poly-N-vinylcaprolactam,and KH2PO4: Experimental and the generalized Flory–Huggins theory

A quaternary (liquid + liquid) equilibrium study was performed to focus attention on the interaction parameters between poly-N-vinylcaprolactam (PVCL) and poly-ethylene glycol (PEG) as well as between other species. At first, the new experimental data of (liquid + liquid) equilibria for aqueous two-phase systems containing PEG, KH₂PO₄, and PVCL at T = 303.15 K have been determined. Then the Flory–Huggins theory with two electrostatic terms (the Debye–Huckel and the Pitzer–Debye–Huckel equations) has been generalized to correlate the phase behavior of the quaternary system. Good agreement has been found between experimental and calculated data from both models especially from the Pitzer–Debye–Huckel equation.Also an effort was done to compare the effect of temperature as well as addition of PVCL on the binodal curves of PEG, KH₂PO₄, and water. The effect of the type of salt on the binodals has been also studied, and the salting out power of the salts has been determined.     

Separation of toluene and heptane by liquid–liquid extraction using z-methyl-N-butylpyridinium tetrafluoroborate isomers (z = 2, 3, or 4) at T = 313.2 K

The (liquid + liquid) equilibrium (LLE) data for three ternary systems containing heptane, toluene, and a z-methyl-N-butylpyridinium tetrafluoroborate ionic liquid ([zbmpy][BF₄] IL, where z = 2, 3, or 4) were determined at T = 313.2 K and atmospheric pressure. The effect of IL cation isomers on the LLE data was evaluated for the first time. The selectivity and extractive capacity from these LLE data were calculated and compared to those previously reported in the literature for the systems (heptane + toluene + [4bmpy][BF₄]) and (heptane + toluene + sulfolane). The results show that the LLE data for the systems comprising the ILs with the metha- and para-substituted cations do not differ significantly from isomer to isomer. On the other hand, significant differences were observed among the systems with the ortho-substituted cation and the other two cation isomers. The degree of consistency of the experimental LLE data was ascertained by applying the Othmer–Tobias correlation. In addition, the LLE data were satisfactorily correlated by means of the thermodynamic NRTL model.     

Liquid–liquid equilibria for ternary systems of (water + carboxylic acid + 1-octanol) at 293.15 K: modeling phase equilibria using a solvatochromic approach

Liquid–liquid equilibrium data of the solubility (binodal) curves and tie-line end compositions are presented for mixtures of [water (1) + formic acid or propanoic acid or levulinic (4-oxopentanoic) acid or valeric (pentanoic) acid or caproic (hexanoic) acid (2) + 1-octanol (3)] at 293.15 K and 101.3 ± 0.7 kPa. A log-basis approach SERLAS (solvation energy relation for liquid associated system) has been proposed to estimate the properties and liquid–liquid equilibria (LLE) of tertiary associated systems containing proton-donating and -accepting components capable of a physical interaction through hydrogen bonding. The model combines the solvatochromic parameters with the thermodynamic factors derived from the UNIFAC-Dortmund model. The reliability of the model has been analyzed against the LLE data with respect to the distribution ratio and separation factor. The tie-lines were also correlated using the UNIFAC-original model. The proposed model, reflecting the simultaneous impact of hydrogen bonding, solubility and thermodynamic factors, yields a mean error of 27.9% for all the systems considered.     

(Liquid + liquid) equilibria in {water + acrylic acid + (1-butanol,or 2-butanol,or 1-pentanol)} systems at T = 293.2 K,T = 303.2 K,and T = 313.2 K and atmospheric pressure

(Liquid + liquid) equilibrium (LLE) data for {water + acrylic acid + (1-butanol, or 2-butanol, or 1-pentanol)} at T = 293.2 K, T = 303.2 K, and T = 313.2 K and atmospheric pressure (≈95 kPa) were determined by Karl Fischer titration and densimetry. All systems present type I binodal curves. The size of immiscibility region changes little with an increase in temperature, but increases according to the solvent, following the order: 2-butanol < 1-butanol < 1-pentanol. Values of solute distribution and solvent selectivities show that 1-pentanol is a better solvent than 1-butanol or 2-butanol for acrylic acid removal from water solutions. Quality of data was ascertain by Hand and Othmer-Tobias equations, giving R² > 0.916, mass balance and accordance between tie lines and cloud points. The NRTL model was used to correlate experimental data, by estimating new energy parameters, with root mean square deviations below 0.0053 for all systems.     

Solubilities and liquid–liquid equilibria of (water + ethanol + α,α,α-trifluorotoluene) at temperatures T = (288.15, 298.15, and 308.15) K and pressure p = 101.2 kPa

New solubility and liquid–liquid equilibrium (LLE) data of solutions of (water + ethanol + α,α,α-trifluorotoluene) are determined at three temperatures (288.15, 298.15, and 308.15) K and atmospheric pressure. The solubility and LLE data are correlated quantitatively by empirical equations, NRTL, and UNIQUAC models. The effect of temperature upon miscibility of the ternary systems is small. Practically, α,α,α-trifluorotoluene is capable to extract efficiently ethanol from its dilute aqueous solutions to obtain absolute alcohol.     

(Liquid + liquid) equilibria of binary systems containing hyperbranched polymer Boltorn® H2004 – Experimental study and modelling in terms of lattice-cluster theory

(Liquid + liquid) phase equilibria (LLE) of binary mixtures containing hyperbranched polymer Boltorn® H2004 and n-alkanes (n-hexane, n-heptane, n-octane, and n-decane) were studied over the temperature range from about (260 up to 360) K. The polymer is partially miscible with n-alkanes and the solubility decreases with an increase of the chain length of the solvent. Corresponding LLE phase diagrams including spinodal and binodal (liquid + liquid) coexistence curves were calculated in terms of the statistical mechanics – based on the lattice-cluster theory, based only on the upper critical solution temperature, and the polymer chain architecture. The results show semi-qualitative agreement of predicted and experimental equilibrium compositions and temperatures. Boltorn® H2004 reveals complete miscibility in the liquid phase with alcohols (C₁–C₈), aromatic hydrocarbons (benzene, toluene, and thiophene), and ethers (methyl tetra-butyl ether, ethyl tetra-butyl ether, and tetrahydrofurane).     

Thermophysical properties of biodiesel and related systems: (Liquid + liquid) equilibrium data for soybean biodiesel

This work reports (liquid + liquid) equilibrium (LLE) data for the systems of interest in soybean biodiesel production. Numerical data for LLE were obtained for binary, ternary and quaternary systems comprising fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE) from soybean oil, water, glycerol, methanol, and ethanol at temperatures of (303.15, 318.15, and 333.15) K. Quantification of compounds in equilibrium in both phases was determined by analytical methods whereas solubility curves (binodal) were obtained by the cloud-point method. For all systems investigated, good alignments were obtained between phase compositions and the initial as well as overall compositions hence indicating low deviations from the mass balance. Experimental results were correlated using the UNIQUAC model with satisfactory agreement between experiment and theory.     

(Liquid + liquid) equilibria for (water + 1-propanol or acetone + β-citronellol) at different temperatures

On this paper, experimental (liquid + liquid) equilibrium (LLE) results are presented for systems composed of β-citronellol and aqueous 1-propanol or acetone. To evaluate the phase separation properties of β-citronellol in aqueous mixtures, LLE values for the ternary systems (water + 1-propanol + β-citronellol) and (water + acetone + β-citronellol) were determined with a tie-line method at T = (283.15, 298.15, and 313.15 ± 0.02) K and atmospheric pressure. The reliability of the experimental tie-lines was verified by the Hand and Bachman equations. Ternary phase diagrams, distribution ratios of 1-propanol and acetone in the mixtures are shown. The effect of the temperature on the ternary (liquid + liquid) equilibria was examined and discussed. The experimental LLE values were satisfactorily correlated by extended UNIQUAC and modified UNIQUAC models.     

Phase equilibria study of the binary systems (1-butyl-3-methylimidazolium tosylate ionic liquid + water,or organic solvent)

(Solid + liquid) phase equilibria (SLE) and (liquid + liquid) phase equilibria (LLE) for the binary systems: ionic liquid (IL) 1-butyl-3-methylimidazolim tosylate (p-toluenesulfonate) {[BMIM][TOS] + water, an alcohol (ethanol, or 1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol), or n-hexane, or an aromatic hydrocarbons (benzene, or toluene, or ethylbenzene, or propylbenzene, or thiophene)} have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (230 to 340) K. For the binary systems containing water, or an alcohol, simple eutectic diagrams were observed with complete miscibility in the liquid phase. As usual, with increasing chain length of the alcohol the solubility decreases. In the case of mixtures {IL + n-hexane, or benzene, or alkylbenzene, or thiophene} the eutectic systems with mutual immiscibility in the liquid phase with an upper critical solution temperature (UCST) were detected. The basic thermal properties of the pure IL, i.e. melting and glass-transition temperatures, as well as the enthalpy of fusion have been measured using a differential scanning microcalorimetry technique (DSC). Density at high temperatures was determined and extrapolated to 298.15 K. Well-known UNIQUAC, Wilson and NRTL equations have been used to correlate experimental SLE data sets for alcohols and water. For the systems containing immiscibility gaps {IL + n-hexane, or benzene, or alkylbenzene, or thiophene}, parameters of the LLE correlation equation have been derived using only the NRTL equation.