Modulating the Solubilities of Ionic Liquid Components in Aqueous-Ionic Liquid Biphasic Systems: A Q-NMR Investigation

Mutual Solubilities between Ethylene Glycol and Organic Diluents: Gas Chromatography and NMR

In this work, the mutual solubilities of sets of organic diluents (CHCl₃, C₆H₆, C₂H₄Cl₂, CCl₄, C₆H₁₂, and n-hexane) with the organic compound ethylene glycol are investigated via gas chromatography (GC). The experimental data measured for these binary organic systems are used to adjust the future nonaqueous systems for the solvent extraction of various metals with ligands. The obtained results showed that the solubility of ethylene glycol decreased in the order CHCl₃ > C₆H₆ > C₂H₄Cl₂ > CCl₄(0%) ≈ C₆H₁₂ ≈ n-hexane. On the other hand, the solubility of the tested traditional organic diluents in ethylene glycol decreased in the following order: C₆H₆ > CHCl₃ > C₂H₄Cl₂ > n-hexane > C₆H₁₂ > CCl₄. ¹H NMR was also used as an analytic method in order to compare the obtained results for the samples showing significant solubility only, including an additional study with 1,2- or 1,3-propanediol. The enhanced solubility of the C₆H₆ compound in ethylene glycol was identified here as critical due to the GC technique, which will be without future consequences in chemical technology. Therefore, it was found that the best molecular diluent for the recovery of metals among the tested ones is C₆H₁₂, with a green protocol as the new paradigm, replacing the aqueous phase with another nonaqueous phase, i.e., a second organic diluent.

Thenoyltrifluoroacetone: Preferable Molecule for Solvent Extraction of Metals—Ancient Twists to New Approaches

A review of the investigations devoted to the solvent extraction processes of metal ions with a chelating ligand thenoyltrifluoroacetone (HTTA) is presented herein. It seems that this molecule has been preferred in the field for more than half a century, and that it is used very often as an extractant for almost all metals. The main objective of the present review is also to provide an overview of the synergistic solvent extraction of lanthanoids, particularly with the use of a β-diketone−neutral mixture. Based on the previous published results in the open literature, the extraction efficiency has been examined in detail and discussed further mainly in terms of the corresponding equilibrium constants among other outlined, so-important parameters. Major conclusions on the role of ligating groups of extractants towards the mechanism, an improved extraction enhancement, and selectivity are additionally provided. The fact that ionic liquids (ILs) appear to be replacing volatile diluents in the field of the liquid–liquid extraction of metals, again with the participation of this β-diketone, is not surprising. As is well known, a very efficient and simple way to determine the stoichiometry of the extracted species in the organic phase is by the simple use of the slope analysis method; however, it is sometimes difficult to perform, either because it somehow requests good solubility of the ligand or because obtained slopes are quite often far from integer values in ILs.

The role of association of ions in ionic liquid/molecular solvent mixtures on metal extraction

Platinum extraction from aqueous phase into ionic liquid can be correlated to ionic association.

Mutual solubility of water and hydrophobic ionic liquids in the presence of hydrochloric acid

Possible mechanism for ionic liquid dissolution in HCl solution.

The interaction of extractants during synergistic solvent extraction of metals. Is it an important reaction?

The target of the review is to provide an overview on the possible interaction between the two ligands during synergistic solvent extraction of metallic species.

Synergism as a phenomenon in solvent extraction of 4f-elements with calixarenes

The objective of the review is to provide an overview on the synergistic solvent extraction of lanthanoids: β-diketone/calixarene mixtures.

Separation of cobalt and nickel using a thermomorphic ionic-liquid-based aqueous biphasic system

A [P44414][Cl]-NaCl-H2O ionic liquid-based aqueous biphasic system shows promising results for the separation of cobalt(II) and nickel(II) by homogeneous liquid-liquid extraction. The extracting phase consists of a hydrophilic ionic liquid that is salted-out by sodium chloride, indicating that there is no need for using hydrophobic ionic liquids.

Coordination Chemistry of Europium(III) Ion Towards Acylpyrazolone Ligands

Two Eu(III) complexes were synthesized using 4-acylpyrazolone ligands: 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one (HPMMBP) and 3-methyl-1-phenyl-4-(4-phenylbenzoyl)-pyrazol-5-one (HPPMBP). The composition of the obtained solid complexes was determined as Eu(PMMBP)3·C2H5OH and Eu(PPMBP)3·3H2O based on elemental analysis and was further studied by IR, NMR and TG-TSC data. The lanthanoid complexation in solid state and in solution during liquid-liquid extraction (molecular diluent and ionic liquid) is discussed.

Are fancy acidic or neutral ligands really needed for synergism in ionic liquids? A comparative study of lanthanoid extraction in CHCl3 and an ionic liquid

Five lanthanoid ions were extracted with 3-methyl-1-phenyl-4-(4-phenylbenzoyl)-pyrazol-5-one in combination with calix[4]arene as a synergistic agent using CHCl₃ or 1-butyl-3-methylimidazolium-bis(trifluoromethanesulfonyl)imide as solvent.