Liquid Phase Equilibria of Aqueous Mixtures of Carboxylic Acids (C₁–C₄) with Ethylbenzene: Thermodynamic and Mathematical Modeling

Abstract

Liquid–liquid equilibrium (LLE) data were experimentally determined and correlated for the aqueous solutions of a series of carboxylic acids (i.e., formic, acetic, propionic, and butyric acids) with ethylbenzene at a temperature of 298.15 K and p = 101.32 kPa. The ternary mixtures containing of the acids exhibit type-1 LLE behavior. The quality of the observed tie-lines was checked using the Othmer–Tobias equation. The correlations were carried out using the thermodynamic and statistical modeling. The activity coefficient models of UNIQUAC and NRTL were applied to fit the tie lines and values of the binary interaction parameters between each pair of components were obtained. The correlation of the tie lines was also carried out by a GMDH type-NN, which are in agreement with those obtained experimentally. In this work, experimental distribution coefficients and separation factors were estimated. Moreover, the Kamlet–Taft LSER model was employed to correlate these quantities and was interpreted in terms of intermolecular interactions.

Experimental and Correlated Liquid–Liquid Equilibrium Data for (Water + Propionic Acid + Ethylbenzene or Benzyl Benzoate) Ternary Systems

“…Figure a,b shows the solubility curves diagrams for the studied systems at T = (298.2, 308.2, and 318.2) K and p = 0.1 MPa. The solubility curve for the system containing ethylbenzene at T = 298.2 K has been reported in our previous publication and is replotted in the same figure for comparison. As shown in the figure, the influence of temperatures on biphasic region is not noticeable for the studied systems.…”

“…The preliminary solubility measurements of the (water + propionic acid + ethylbenzene) system was compared with our reported data under the same temperature and pressure (at T = 298.2 and P = 0.1 MPa) in order to establish the reliability of the procedure. The experimental solubility data for the (water + propionic acid + ethylbenzene or benzyl benzoate) systems at different temperatures were determined by the cloud point method and listed in Table .…”

“…In our previous LLE studies, the equilibrium data for the aqueous solutions of PA with different organic solvents have been reported. − As an extension of the previous work, we report the LLE data for the ternary aqueous mixtures of propionic acid and aromatic solvents at T = (298.2, 308.2, and 318.2) K and p = 0.1 MPa. In this research, benzyl benzoate (BB, Figure b) and ethylbenzene (EB, Figure c) were tested as organic solvents for separation of PA from water.…”

Comparative Evaluation of the Liquid–Liquid Equilibria of the Extraction of Valeric or Caproic Acids from Water by Esters

“…The experimental set-up and extraction procedure of the ternary systems was based on our previously publication . The process can be divided into three different stages: solubility curves measurement, tie line measurement, and analysis.…”

“…The rapid growing required LLE data for the separation of carboxylic acids from water has been highlighted in earlier studies. − Many organic solvents with different functional groups have been tested as extractants for efficient separation operations. − Among the carboxylic acids, valeric acid (VA) and caproic acid (CA) are important chemicals (Figure a) because of their wide industrial applications . These carboxylic acids are mostly applied in the synthesis of esters and lubricants.…”