Three-liquid-phase behavior in the quaternary systems of water + phosphoric acid + diisopropyl ether + tributyl phosphate/methyl isobutyl ketone at 298.2 K

• Published in: Journal of molecular liquids 2024-11, Vol.413, p.126061, Article 126061
• Main Authors: Mouhib, Mohamed, Kaddami, Mohammed, Counioux, Jean-Jacques, Goutaudier, Christelle
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Diisopropyl ether; H3PO4; Liquid–liquid equilibria; Methyl isobutyl ketone; Quaternary systems; Tributyl phosphate; WPA
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2024.126061

[Display omitted] •LLE data for the quaternary systems of H2O+H3PO4 + DIPE+TBP/MIBK.•Study of the effect of TBP and MIBK on the three-phase zone.•Three-phase zone disappeared after the addition of 0.206 of TBP and 0.583 of MIBK.•The mixed solvent (TBP+DIPE) is the best-performing solvent.•The mixed solvent (0.3TBP+0.7DIPE) has the potential to enhance H3PO4 extraction. The three-liquid-phase formation in the ternary system of water + phosphoric acid + diisopropyl ether (DIPE) makes the phosphoric acid extraction only effective for acid mass fractions above 0.69. To avoid the undesirable formation of the third phase and enhance acid extraction, particularly at low concentrations, two phase modifiers, methyl isobutyl ketone (MIBK) and tributyl phosphate (TBP), were systematically studied. In order to quantify the synergetic effect of the mixed solvents of DIPE+TBP and DIPE+MIBK, the liquid–liquid equilibria for the quaternary systems of H2O+H3PO4 + DIPE+TBP and H2O+H3PO4 + DIPE+MIBK were fully established for different DIPE/phase modifier (TBP or MIBK) mass ratios (90/10, 70/30, 50/50, and 20/80) at 298.2 K under atmospheric pressure using the cloud point and Othmer graphical method. Othmer-Tobias and Hand correlations were used to fit the tie-line data and assess its consistency. In addition, the behavior of the three-phase zone was also studied as a function of the phase modifiers content. Separation factor (S) and acid distribution (D2) were used to identify the most effective solvent with the potential to enhance phosphoric acid extraction from aqueous solutions.