Liquid–Liquid Equilibria for Separation of Alcohols from Esters Using Deep Eutectic Solvents Based on Choline Chloride: Experimental Study and Thermodynamic Modeling (original) (raw)
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Journal of Chemical & Engineering Data, 2018
Choline chloride-based deep eutectic solvent (DES) was tested for the separation of azeotropic mixtures of ethanol−ethyl acetate, n-propanol−n-propyl acetate and nbutanol−n-butyl acetate via liquid−liquid extraction. The mixture of choline chloride with malonic acid with a molar ratio of 1:1 was used. Extraction experiments were conducted with the ternary mixture ethanol−ethyl acetate−DES at temperatures 293.15, 303.15, and 313.15 K and with ternary mixtures npropanol−n-propyl acetate−DES and n-butanol−n-butyl acetate−DES at 293.15, 303.15, 313.15, and 323.15 K. Liquid− liquid tie-lines for studied systems were determined. The extraction performance of DES was characterized with solute distribution coefficients and values of selectively respectively to alcohol. The influence of the alkyl chain length of the alcohol and ester on the phase equilibria was investigated. Experimental data were fitted using the nonrandom two liquids model.
Journal of Chemical & Engineering Data, 2018
In this study, the COSMO-RS approach was used to qualitatively and quantitatively screen five choline chloride-based deep eutectic solvents (DESs) to separate the azeotropic binary formed between benzene and either methanol or ethanol. The activity coefficient at infinite dilution was calculated to evaluate the capacity, selectivity, and performance index of each DES. The interactions between the different species were also analyzed by interpreting the σprofile and σ-potential of each component. Then, three DESs were selected for experimental validation. They were prepared by combining choline chloride with ethylene glycol, levulinic acid, and 1,2-propanediol. The best performance in terms of distribution ratio and selectivity was achieved with choline chloride/ethylene glycol DES with 1:4 molar ratio. The experimental tie-lines were successfully correlated using the NRTL model. Regardless of the system investigated, no DES was found in the raffinate phase, implying minimal cross-contamination. Finally, 2D NMR analysis was conducted to study the extraction mechanism of alcohol and its effect on the DES structure. This analysis revealed that, when the alcohol concentration exceeds 40 mol %, the DES' hydrogen bonds are broken such that only one phase occurs and thus the separation becomes impractical.
The ability of non-toxic and biodegradable deep eutectic solvent (DES) choline chloride + dl-malic acid in molar ratio 1:1, for breaking the azeotropes heptane + methanol and toluene + methanol by means of liquidliquid extraction was evaluated. Ternary liquid-liquid equilibrium experiments were performed at 298.15 K and at atmospheric pressure. Densities, viscosities and refractive indices of DES + methanol and water + DES systems were experimentally determined over a wide temperature range and at atmospheric pressure. Additionally, viscosities of DES + glycerol mixture were determined at temperatures up to 363.15 K to check how much the addition of glycerol decreases high viscosities of DES. The results indicate that addition of small amounts of water or glycerol as a third component significantly decreases viscosity of the investigated deep eutectic solvent. Based on selectivity and distribution ratio values, extraction ability of the investigated deep eutectic solvent, in comparison with conventionally used solvents, yields promising results. Non-random two-liquid (NRTL) and Universal quasichemical (UNIQUAC) models were satisfactorily applied for correlation of experimental phase equilibrium data for two ternary mixtures.
Fluid Phase Equilibria, 2017
The extraction of aromatic hydrocarbons from reformer and pyrolysis gasolines is currently performed by liquid-liquid extraction using organic solvents. Deep eutectic solvents (DES) are being widely studied as environmentally benign alternatives to conventional solvents since DES can be prepared using nontoxic and renewable chemicals. In this work, we have studied for the first time the application of DES in the extraction of aromatic hydrocarbons from reformer and pyrolysis gasolines. We have tested six choline chloride-based DES formed by ethylene glycol, glycerol, levulinic acid, phenylacetic acid, malonic acid, and urea as hydrogen bond donors. COSMO-RS method was employed to predict the performance of the DES in the extraction of aromatics, whereas experimental results indicate that DES formed by choline chloride and levulinic acid has exhibited the most adequate extractive and physical properties. Afterward, the simulation and optimization of the whole process for extraction of aromatics, recovery of extracted hydrocarbons, and regeneration of the solvent have been performed. The proposed process of dearomatization could work at moderate temperatures using a cheap, sustainable, and nontoxic solvent.
Kemija u industriji
Liquid-liquid equilibria were experimentally investigated in systems in which the first component was aliphatic (n-hexane, n-heptane or i-octane) or aromatic hydrocarbon (toluene), the second component was pyridine or thiophene, and the third quasi-component was DES consisting of choline chloride and glycerol or choline chloride and ethylene glycol, at 25 °C and atmospheric pressure. The equilibria were successfully described by the NRTL and UNIQUAC models. The same models were successfully applied to describe the liquid-liquid equilibria in quasi-seven-component systems that comprised all the mentioned low molecular weight components and one DES. The restrictions of the models were discussed; it seems that the preference can be given to the UNIQUAC model.
Solvent Extraction of Ethanol from Aqueous Solutions. I. Screening Methodology for Solvents
Industrial & Engineering Chemistry Research, 2005
Distribution coefficients have been measured for the partitioning of ethanol and water from aqueous mixtures into 57 different alcohol solvents. The study has focused on the effects of systematic variations in chemical structure of the alcohols. Factors found to be important include chain length and hydroxyl position for the x-alcohols (i.e., 1-heptanol through 1-dodecanol, 2-heptanol through 2-undecanol, etc.), branch structure (e.g., methyl, ethyl, n-propyl, i-propyl, etc.) for a branch located on the hydroxyl carbon, location of the branch relative to the hydroxyl carbon, and multiple branching.
Fluid Phase Equilibria, 2018
Solute retention data acquired by gas-liquid chromatography were used to determine the activity coefficients at infinite dilution for 24 organic solutes in the deep eutectic solvent (DES) consisting of tetramethylammonium chloride and glycerol in a molar ratio of 1.001:2. The organic solutes included alk-1anes, alk-1-enes, alk-1-ynes, cycloalkanes, alkanols, alkylbenzenes, ketones, esters and heterocyclics. The measurements were undertaken at four different temperatures, viz T ¼ (313.15, 323.15, 333.15 and 343.15) K with an estimated uncertainty of ±3.8%. From the experimental infinite dilution activity coefficient data, the values of partial molar excess enthalpy at infinite dilution were calculated using Gibbs Helmholtz relationship. Limiting selectivity and capacity values were also calculated from experimental limiting activity coefficients and compared to those of other separation agents, including other deep eutectic solvents, ionic liquids and industrial molecular agents. Results obtained in this study indicate that tetramethylammonium chloride þ glycerol DES can potentially be used as an alternative solvent for nitrogen and sulphur removal from transportation fuels as well as the separation of cycloalkanes, aromatics and esters from light alkanols.
Liquid–liquid equilibrium (LLE) data for the quaternary systems (water + ethanol + dichloromethane (DCM) or chloroform (CHCl3) + diethyl ether (DEE)) were experimentally investigated at 293.15 K. The thermodynamic consistency of the data was performed using the Othmer–Tobias and Hand plots. The experimental tie-line data were correlated using the non-random, two-liquid (NRTL) model. As a result, the comparison of the extracting capabilities of the mixed solvents with respect to the distribution coefficients and separation factors showed that the (50% DCM +50% DEE) system had a higher separation factor for the (water + ethanol + DCM + DEE) system. On the other hand, the (50% CHCl3 +50% DEE) system had a higher separation factor for the (water + ethanol + CHCl3 + DEE) system. The last solvent (50% CHCl3 +50% DEE) was found to be the best solvent, with a positive synergistic effect on DEE, high separation factor, and very low solubility in water.