(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 + 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.     

(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 + 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 the (water + butyric acid + dodecanol) ternary system

(Liquid + liquid) equilibrium (LLE) data for the (water + butyric acid + dodecanol) ternary system have been determined experimentally at T = (298.2, 308.2 and 318.2) K. Complete phase diagrams were obtained by determining binodal curves and tie lines. The reliability of the experimental tie lines was confirmed by using the Othmer–Tobias correlation. The UNIFAC method was used to predict the phase equilibrium in the ternary system using the interaction parameters determined from experimental data of CH₃, CH₂, COOH, OH and H₂O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Liquid–liquid equilibria of ternary systems (water + carboxylic acid + cumene) at 298.15 K

(Liquid–liquid) equilibrium data for the ternary systems [water + formic acid or acetic acid or propionic acid + cumene (2-phenylpropane, isopropylbenzene)] at 298.15 K are reported. Complete phase diagrams were obtained by determining solubility and the tie-line data. The reliability of the experimental tie-lines was determined through the Othmer–Tobias plots. Distribution coefficients and separation factors were evaluated for the immiscibility region. The tie-line data were compared with the results predicted by the UNIFAC method.     

(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.     

Phase equilibria for ternary liquid systems of (water + tetrahydrofuran + nonprotic aromatic solvent) at T = 298.2 K

(Liquid + liquid) equilibrium (LLE) data of the solubility curves and tie-line end compositions are presented for mixtures of {water (1) + tetrahydrofuran (2) + xylene or chlorobenzene or benzyl ether (3)} at T = 298.2 K and P = (101.3 ± 0.7) kPa. Among the studied C6 ring-containing aromatic solvents, xylene gives the largest distribution ratio and separation factors for extraction of tetrahydrofuran. A solvation energy relation (SERLAS) has been used to estimate the (liquid + liquid) equilibria of associated systems containing a nonprotic solvent. The tie-lines were also predicted using the UNIFAC-original model. The reliability of both models has been analyzed against the LLE data with respect to the distribution ratio and separation factor. SERLAS matches LLE data accurately, yielding a mean error of 9.9% for all the systems considered.     

Liquid–liquid equilibria of the ternary system water + acetic acid + dimethyl succinate

Liquid–liquid equilibrium (LLE) data of water + acetic acid + dimethyl succinate were measured at 298.2, 308.2, and 318.2 K. Complete phase diagrams were obtained by determining binodal curves and tie lines. The reliability of the experimental tie line data was confirmed by using the Othmer–Tobias correlation. The UNIFAC and modified UNIFAC model were used to predict the phase equilibrium data in the ternary system. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Measurement and modeling of high-pressure (vapour + liquid) equilibria of (CO2 + alcohol) binary systems

An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at <5%. Complementary isothermal (vapour + liquid) equilibria results are reported for the (CO₂ + 1-propanol), (CO₂ + 2-methyl-1-propanol), (CO₂ + 3-methyl-1-butanol), and (CO₂ + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO₂ + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng–Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) equilibria compositions were found to be in good agreement with the experimental values with deviations for the mol fractions <0.12 and <0.05 for the liquid and vapour phase, respectively.     

(Liquid + liquid) equilibria of (water + linalool + limonene) ternary system at T = (298.15, 308.15, and 318.15) K

(Liquid + liquid) equilibrium (LLE) data for {water (1) + linalool (2) + limonene (3)} ternary system at T = (298.15, 308.15, and 318.15 ± 0.05) K are reported. The organic chemicals were quantified by gas chromatography using a flame ionisation detector while water was quantified using a thermal conductivity detector. The effect of the temperature on (liquid + liquid) equilibrium is determined and discussed. Experimental data for the ternary mixture 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 a good correlation of the solubility curve at these three temperatures, while comparing the calculated values with the experimental ones, the best fit is obtained with the NRTL model. Finally, the UNIFAC model provides poor results, since it predicts a greater heterogeneous region than experimentally observed.     

Experimental (vapour + liquid) equilibrium data of (methanol + water), (water + glycerol) and (methanol + glycerol) systems at atmospheric and sub-atmospheric pressures

Experimental (vapour + liquid) equilibrium results for the binary systems, (methanol + water) at the local atmospheric pressure of 95.3 kPa and at sub-atmospheric pressures of (15.19, 29.38, 42.66, 56.03, and 67.38) kPa, (water + glycerol) system at pressures (14.19, 29.38, 41.54, 54.72, 63.84, and 95.3) kPa and the (methanol + glycerol) system at pressures (32.02 and 45.3) kPa were obtained over the entire composition range using a Sweitoslwasky-type ebulliometer. The relationship of the liquid composition (x₁) as a function of temperature (T) was found to be well represented by the Wilson model. Computed vapour phase mole fractions, activity coefficients and the measured values along with optimum Wilson parameters are presented.     

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 of (water + ethanol + dimethyl glutarate) at several temperatures

(Liquid + liquid) equilibrium (LLE) data of (water + ethanol + dimethyl glutarate) have been determined experimentally at T=(298.15,308.15 and 318.15) K. The reliability of the experimental tie-line data was ascertained by using the Othmer and Tobias correlation. The LLE data of the ternary mixture were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Phase transitions on (liquid + liquid) equilibria for (water + 1-methylnaphthalene + light aromatic hydrocarbon) ternary systems at T = (563, 573, and 583) K

Phase transitions for (water + 1-methylnaphthalene + light aromatic hydrocarbon) ternary systems are observed at their (liquid + liquid) equilibria at T = (563, 573, and 583) K and (8.6 to 25.0) MPa. The phase transition pressures at T = (563, 573, and 583) K were measured for the five species of light aromatic hydrocarbons, o-, m-, p-xylenes, ethylbenzene, and mesitylene. The measurements of the phase transition pressures were carried out by changing the feed mole fraction of water and 1-methylnaphthalene in water free, respectively. Effects of the feed mole fraction of water on the phase transition pressures are very small. Increasing the feed mole fraction of 1-methylnaphthalene results in decreasing the phase transition pressures at constant temperature. The slopes depending on the feed mole fraction for 1-methylnaphthalene at the phase transition pressures are decreased with increasing temperature for (water + 1-methylnaphthalene + p-xylene), (water + 1-methylnaphthalene + o-xylene), and (water + 1-methylnaphthalene + mesitylene) systems. For xylene isomers, the highest and lowest of the phase transition pressures are obtained in the case of p- and o-xylenes, respectively. The phase transition pressures for ethylbenzene are lower than those in the case of p-xylene. The similar phase transition pressures are given for p-xylene and mesitylene.     

Quaternary liquid–liquid equilibria for systems of {(water + methanol or ethanol) + m-xylene + n-dodecane}

Liquid–liquid equilibrium (LLE) data were determined for the quaternary systems of {(water + methanol or ethanol) + m-xylene + n-dodecane} at three temperatures 298.15, 303.15 and 313.15 K and atmospheric pressure. The composition of liquid phases at equilibrium was determined by gas–liquid chromatography and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of the solvent are calculated and compared. The phase diagrams for the quaternary systems including both the experimental and correlated tie lines are presented.     

(Liquid + liquid) equilibria for ternary mixtures of (water + propionic acid + organic solvent) at T = 303.2 K

Experimental tie-line results and phase diagrams were obtained for the ternary systems of {water + propionic acid + organic solvent (cyclohexane, toluene, and methylcyclohexane)} at T = 303.2 K and atmospheric pressure. The organic solvents were two cycloaliphatic hydrocarbons (i.e., cyclohexane and methylcyclohexane) and an aromatic hydrocarbon (toluene). The experimental tie-lines values were also compared with those calculated by the UNIQUAC and NRTL models. The consistency of the values of the experimental tie-lines was determined through the Othmer–Tobias and Hands plots. Distribution coefficients and separation factors were evaluated over the immiscibility regions and a comparison of the extracting capabilities of the solvents was made with respect to distribution coefficients and separation factors. The Kamlet LSER model was applied to correlate distribution coefficients and separation factors in these ternary systems. The LSER model values showed a good regression to the experimental results.     

High-pressure (vapour + liquid) equilibria for ternary systems composed by {(E)-2-hexenal or hexanal + carbon dioxide + water}: Partition coefficient measurement

A new apparatus based on a static–analytic method assembled in this work was utilised to perform high-pressure (vapour + liquid) equilibria measurements of aqueous ternary systems. This work includes values of isothermal partition coefficients between CO₂ and water of two apple aroma constituents, (E)-2-hexenal and hexanal. Additionally, this work reports new experimental (vapour + liquid) equilibria measurements for the ternary systems (CO₂ + (E)-2-hexenal + water) and (CO₂ + hexanal + water), at fixed liquid phase composition (600 mg · kg⁻¹), at temperatures of (313, 323 and 333) K and at pressures from (8 to 19) MPa. Vapour liquid interphase was checked and monitored visually for all the systems studied in this work. No liquid immiscibility was observed at the composition, temperatures and pressures studied. In order to suggest reasonable operation conditions for fractionation of aromas with dense carbon dioxide, partition coefficients of the aroma compounds between CO₂ and water along with their separation factors from water were calculated. Partition coefficients of (E)-2-hexenal between CO₂ and water were in the range of (6 to 91) and where found to be near six times higher than those of hexanal (9 to 17). Very high separation factors from water were observed (∼10⁴) especially for (E)-2-hexenal. The highest separation factor, for both compounds, was found at a temperature of 313 K and pressures from (12 to 14) MPa.