Tie-line Compositions Research Articles

Liquid–liquid equilibria of water + 2,3-butanediol + ethyl acetate at several temperatures

Liquid–liquid equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 2,3-butanediol + ethyl acetate) at 298.15, 308.15 and 318.15 K and atmospheric pressure. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie lines has been confirmed by using Othmer–Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC method.

Liquid–liquid equilibrium of ternary systems 1-butyl-3-methylimidazolium hexafluorophosphate + aromatic + aliphatic

Liquid–liquid equilibrium data for the ternary systems nonane + benzene + [bmim][PF 6], nonane + toluene + [bmim][PF 6], nonane + m-xylene + [bmim][PF 6], undecane + benzene + [bmim][PF 6], undecane + toluene + [bmim][PF 6], undecane + m-xylene + [bmim][PF 6]) were determined at 298.15 K. Binodal curves were obtained by the cloud point method, while tie-line compositions were obtained by density and UV spectrophotometry measurements. In all cases the two-phase region is large and wide. The values of distribution coefficients and selectivities indicate that the ionic liquid [bmim][PF 6] is a good solvent for the extraction of aromatic from aliphatic compounds. The consistency of the tie-line data was ascertained by applying the Othmer–Tobias correlation. The experimental LLE data were correlated through the well-known NRTL model for the activity coefficient, with estimation of new interaction energy parameters, using the Simplex minimization method and a composition-based objective function. The results, analyzed in terms of root mean square deviations between experimental and calculated compositions, were considered satisfactory.

Liquid–Liquid Equilibria of Water + 2,3-Butanediol + Butyl Acetate at T = 298.15 K, T = 308.15 K, and T = 318.15 K

Liquid–liquid equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 2,3-butanediol + butyl acetate) at (298.15, 308.15, and 318.15) K and atmospheric pressure. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The Othmer−Tobias correlation provides the coefficients of the log–log plot that is not a sensitive criterion. The LLE data of the ternary systems have been predicted by UNIFAC methods.

Re-Cr-Ni 系における 1423 K の等温状態図の実験的決定

Compositions with tie-lines between the γ, α, σ, and δ phases in a ternary Re-Cr-Ni system were investigated by heat-treating various ternary Re-Cr-Ni alloys in vacuum at 1423 K for a variety of heating times up to 2500 h. The microstructures of the Re-Cr-Ni alloys that had been water-quenched after heating were observed and their Re, Cr and Ni concentration profiles were measured using an electron probe micro-analyzer (EPMA). It was found that a very long heat treatment was required to obtain equilibrium compositions of Ar-arc-melted Re-Cr-Ni alloys. The tie-line compositions (at%) of each phase at 1423 K were experimentally determined, and an isothermal phase diagram was constructed. From these results, the γ, α, and σ phases of the three-phase coexistence state were found to have the following compositions: γ phase (3.0 at%Re, 45.6 at%Cr, and 51.4 at%Ni), α phase (16.1 at%Re, 75.2 at%Cr, and 8.7 at%Ni), and σ phase (16.3 at%Re, 60.3 at%Cr, and 23.4 at%Ni). In addition, the γ, σ, and δ phases have the following compositions: γ phase (13.3 at%Re, 18.1 at%Cr, and 68.6 at%Ni), σ phase (54.6 at%Re, 24.2 at%Cr, and 21.2 at%Ni), and δ phase (70.2 at%Re, 6.0 at%Cr, and 23.8 at%Ni). The solubility limits of Ni in the σ phase increased from 19 at%Ni to 24 at%Ni, as the Cr content in the σ phase with a tie-line with the γ phase increased from 23 at%Cr to 61 at%Cr.

Liquid–liquid equilibria of water + 2,3-butanediol + 1-butanol at T = 298.15 K, T = 308.15 K and T = 318.15 K

(Liquid–liquid) equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 2,3-butanediol + 1-butanol) at 298.15, 308.15 and 318.15 K and atmospheric pressure. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using Othmer–Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC method.

Ternary liquid–liquid equilibria for mixtures of an ionic liquid + n-hexane + an organic compound involved in the kinetic resolution of rac-1-phenyl ethanol ( rac-1-phenyl ethanol, vinyl propionate, rac-1-phenylethyl propionate or propionic acid) at 298.2 K and atmospheric pressure

The liquid–liquid equilibrium of 16 ternary systems containing an ionic liquid + n-hexane + an organic compound involved in the racemic resolution of rac-1-phenylethanol ( rac-1-phenylethanol, vinyl propionate, 1-phenylethyl propionate or propionic acid) at 298.2 K and atmospheric pressure have been measured. The ionic liquids used were (i) 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim +][PF 6 −]; (ii) 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim +][BF 4 −]; (iii) 1-ethyl-3-methylimidazolium tosilate, [emim +][TOS −] and (iv) 1-butyl-3-methyl imidazolium ethylenglykolmonomethylethersulfate, [bmim +][MDEGSO 4 −]. The binodal curves and the tie line compositions of the conjugate solutions were obtained by means of refractive index (ionic liquid rich phase) and by gas cromatography (hexane rich phase) to determine their potential for selectively extracting organic compounds from an ionic liquid reaction mixture. The tie lines were correlated by using the NTRL equation, which provides good correlation of the experimental data.

Measurement and Correlation of Liquid−Liquid Equilibria of Two Imidazolium Ionic Liquids with Thiophene and Methylcyclohexane

Equilibrium studies on the extraction of thiophene from its mixtures with methylcyclohexane using two imidazolium ionic liquids have been carried out. LLE data were obtained for mixtures of 1-methyl-3-octylimidazolium bis[trifluoromethylsulfonyl]imide or l-methyl-3-octylimidazolium tetrafluoroborate with thiophene and methylcyclohexane at atmospheric pressure and 298.15 K. Tie-line compositions were correlated using the NRTL equation, but considerable deviations from experimental data were found at high concentrations of thiophene. Distribution coefficients and selectivities were evaluated.

Liquid−Liquid Equilibria for Ternary Systems of Water + Formic Acid + Dibasic Esters

Liquid−liquid equilibrium (LLE) data including solubility curves and tie-line compositions were measured for mixtures of water (1) + formic acid (2) + dimethyl succinate or dimethyl glutarate or dimethyl adipate (3) at T = 298.2 K and atmospheric pressure, p = (101.3 ± 0.7) kPa. The relative mutual solubility of the formic acid is higher in the aqueous phase than in the dibasic ester phases. 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 and modified UNIFAC methods. Distribution coefficients and separation factors were evaluated for the immiscibility region.

Measurement and Correlation of Liquid−Liquid Equilibria of Methylcyclohexane + Toluene + N-Formylmorpholine at (293, 303, 313, and 323) K

Liquid−liquid equilibrium (LLE) data for ternary systems methylcyclohexane (1) + toluene (2) + N-formylmorpholine (NFM) (3) were determined under atmospheric pressure and at temperatures of (293.15, 303.15, 313.15, and 323.15) K. Complete phase diagrams were obtained by determining solubility and tie-line data. Tie-line compositions were correlated by the Othmer−Tobias and Bachman methods. The universal quasichemical activity coefficient (UNIQUAC) and the nonrandom two-liquid (NRTL) equation were used to correlate the phase equilibrium in the system using the interaction parameters determined from experimental data. Distribution coefficients, separation factors, and selectivity were evaluated for the immiscibility regions.

Experiment and Correlation of Liquid−Liquid Equilibria of an Aqueous Salt Polymer System Containing PEG6000 + Sodium Citrate

Liquid−Liquid equilibrium data were obtained for an aqueous two-phase system containing poly(ethylene glycol)6000 (PEG6000) + sodium citrate + water at three different temperatures, 293.15, 303.15, and 313.15 K. An empirical equation relating the concentrations of PEG6000 and sodium citrate was used to fit the binodal curve, and the coefficients were estimated for the corresponding temperatures. The effect of temperature on binodal and tie line data was studied. The Othmer−Tobias and Bancraft equations were used to correlate the tie line compositions, and the parameters are reported.

(Liquid + liquid) equilibria of {heptane + xylene + N-formylmorpholine} ternary system

(Liquid + liquid) equilibrium (LLE) data for ternary system {heptane (1) + m-xylene (2) + N-formylmorpholine (3)} have been determined experimentally at temperatures ranging from 298.15 K to 353.15 K. Complete phase diagrams were obtained by determining solubility and tie-line data. Tie-line compositions were correlated by Othmer–Tobias and Bachman methods. The universal quasichemical activity coefficient (UNIQUAC) and The non-random two liquids equation (NRTL) were used to correlate the phase equilibrium in the system using the interaction parameters determined from experimental data. It is found that UNIQUAC and NRTL used for LLE could provide a good correlation. Distribution coefficients, separation factors, and selectivity were evaluated for the immiscibility region.

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

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

(Liquid + liquid) equilibria of three ternary systems: (heptane + benzene + N-formylmorpholine), (heptane + toluene + N-formylmorpholine), (heptane + xylene + N-formylmorpholine) from T = (298.15 to 353.15) K

(Liquid + liquid) equilibrium (LLE) data for ternary systems: (heptane + benzene + N-formylmorpholine), (heptane + toluene + N-formylmorpholine), and (heptane + xylene + N-formylmorpholine) have been determined experimentally at temperatures ranging from 298.15 K to 353.15 K. Complete phase diagrams were obtained by determining solubility and tie-line data. Tie-line compositions were correlated by Othmer–Tobias and Bachman methods. The universal quasichemical activity coefficient (UNIQUAC) and the non-random two liquids equation (NRTL) were used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data. It is found that UNIQUAC and NRTL used for LLE could provide a good correlation. Distribution coefficients, separation factors, and selectivity were evaluated for the immiscibility region.

Liquid−Liquid Equilibrium of Poly(ethylene glycol) 2000 + Potassium Citrate + Water at (25, 35, and 45) °C

Liquid−liquid equilibrium for an aqueous two-phase system containing poly(ethylene glycol) 2000 + potassium citrate + water was studied at three different temperatures of (25, 35, and 45) °C. The binodal curve was fitted to an empirical equation relating the concentrations of PEG 2000 and potassium citrate, and the coefficients were estimated for the respective temperatures. Tie line compositions were correlated using Othmer−Tobias and Bancroft equations, and the parameters are also reported.

Phase Equilibrium Compositions, Densities, and Viscosities of Aqueous Two-Phase Poly(ethylene glycol) + Poly(acrylic acid) System at Various Temperatures

The effect of temperature on the densities and viscosities of aqueous solution of poly(acrylic acid) (PAA) of different mass fraction (from 0.05 to 0.50) and liquid−liquid equilibrium, densities, and viscosities for the aqueous two-phase PEG-6000 + PAA + water system at equilibrium have been measured. The densities and viscosities of the PAA + water system at different temperatures were correlated as a function of mass fraction. The binodal curves for the PEG + PAA + water system have been correlated using a four-parameter equation. The increase in temperature results in an increase in the two-phase region. The tie line compositions have been fitted to both the Othmer−Tobias and the Bancroft equations. A linear dependency of both the plots indicates the consistency of the data; however, the Bancroft equation gives the best fit.

PHASE EQUILIBRIUM FOR TERNARY LIQUID SYSTEMS OF WATER + CARBOXYLIC ACID + CHLORINATED HYDROCARBON: THERMODYNAMIC MODELING THROUGH SERLAS

ABSTRACT Liquid-liquid equilibrium data of the solubility (binodal) curves and tie-line end compositions are presented for mixtures of [water (1) + formic acid, or acetic acid, or propanoic acid (2) + chlorobenzene, or 1,2-dichloroethane (3)] at T = 293.2 K and P = 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 equilibrium (LLE) of associated systems containing proton-donating and -accepting and polar components capable of a physical interaction through hydrogen bonding or dipole-dipole interaction. The tie lines were also correlated using the UNIFAC-original model. The reliability of the models has been analyzed against the LLE data with respect to the distribution coefficient and separation factor. The proposed model appears to be an improvement in data fit for the ternary systems, yielding a mean relative error of 10.1% for all the systems considered.

Ternary (liquid + liquid) equilibria for mixtures of 1-hexyl-3-methylimidazolium (tetrafluoroborate or hexafluorophosphate) + benzene + an alkane at T=298.2 K and p=0.1 MPa

Ternary (liquid + liquid) equilibrium data are presented for mixtures of 1-hexyl-3-methylimidazolium (tetrafluoroborate or hexafluorophosphate) + benzene + (heptane or dodecane or hexadecane) at T=298.2 K. The tie line compositions of the conjugate solutions were obtained by means of density measurements and a standard density calibration curve. Large regions of immiscibility (increasing in the order of hexadecane > dodecane > heptane) and favourable skewing of the tie lines towards the solvent axis provide indications of the favourable use of the ionic liquids in solvent extraction. Selectivity values computed from the experimental data confirm this. Correlation of the experimental tie lines was conducted through the use of the NTRL equation, which provides good correlation of the experimental data.

(Liquid + liquid) equilibria of (water + butyric acid + isoamyl alcohol) ternary system

(Liquid + liquid) equilibrium (LLE) data for the ternary system (water + butyric acid + isoamyl alcohol) have been determined experimentally at T = (298.15, 308.15 and 318.15) K. Complete phase diagrams were obtained by determining solubility and the tie-line data. Tie-line compositions were correlated by Othmer–Tobias method. The UNIFAC method was used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data between groups CH 3, CH 2, CH, COOH, OH and H 2O. It is found that UNIFAC group interaction parameters used for LLE could not provide a good prediction. Distribution coefficients and separation factors were evaluated for the immiscibility region.

(Liquid + liquid) equilibria of (water + butyric acid + cyclohexyl acetate) ternary system

(Liquid + liquid) equilibrium (LLE) data for the ternary system (water + butyric acid + cyclohexyl acetate) have been determined experimentally at T = (298.15, 308.15 and 318.15) K. Complete phase diagrams were obtained by determining solubility and the tie-line data. Tie-line compositions were correlated by the Othmer–Tobias method. The UNIFAC method was used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data between CH, CH 2, CH 3, COOH, CH 3COO and H 2O groups. It is found that UNIFAC group interaction parameters used for LLE could not provide a good prediction. Distribution coefficients and separation factors were evaluated for the immiscibility region.

LIQUID-LIQUID EQUILIBRIA OF THE WATER+ETHANOL+DIMETHYL ADIPATE TERNARY SYSTEM

Liquid-liquid equilibrium data for the terna1y system water-ethanol-dimethyl adipate (dibasic ester) have been determined experimentally at 298.15±0.20, 308.15±0.20, and 318.15±0.20 K. Tie-line compositions were correlated by the Othmer-Tobias method. The UNIFAC method was used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data between the CH3, CH2, OH, CH3COO and H20 groups. Distribution coefficients and separation factors were evaluated for the immiscibility region