Lanthanoid complexes with thenoyltrifluoroacetone and 4-tert-butylcalix[4]arene-tetraacetic acid tetraethyl ester: synergistic extraction and separation

Comparing extraction, synergism and separation of lanthanoids using acidic and neutral compounds in chloroform and one ionic liquid: is the latter always “better”?

“…1 Concerning the SF values, a moderate selectivity has been noticed with the present systems as compared to the case when similar extraction systems were used. 6 Extraction, synergism and separation in IL (2.67). This result is in line with previous ones obtained for ILs of the same family under various acidic conditions (in particular, 1 M nitric acid).…”

“…The samples were shaken mechanically (Orbital Shaker OS-20, Boeco, Germany, 120 rpm) for 45 minutes at room temperature (22 AE 2 C) which was sufficient to reach equilibrium. [1][2][3][4][5][6][7][8] Aer the separation of the phases, the metal concentration in the aqueous phase was determined spectophotochemically (S-20 Spectrophotometer Boeco, Germany) using Arsenazo III. 38 The concentration of the metal ion in the organic phase was calculated by subtraction of the determined amount in the aqueous phase from the total amount present.…”

“…As part of our systematic work on the synergistic solvent extraction of lanthanoids, [1][2][3][4][5][6][7][8] we performed comparative studies aiming at (i) improving the extraction ability of b-diketone compounds by increasing their acidity, (ii) studying the dependence of the extraction properties on the number of the ligating groups on a calixarene scaffold and nally, (iii) understanding the role of the solvent for extraction, separation and synergism by comparing a traditional molecular solvent, chloroform, and one ionic liquid, namely 1-methyl-3-butylimidazolium bis(triuoromethanesulfonyl)imide, there-aer denoted as [C 1 C 4 im][Tf 2 N]. It is our opinion that the wellassessed strategy based on the individual independent improvements of the extractants used in a synergistic system, which has proven to be quite efficient in molecular solvents, [1][2][3][4][5][6][7][8] may nd some limitations in ionic liquids (ILs). Ionic liquids are studied for an increasing number of applications in various aspects of chemistry and of course liquid-liquid extraction of rare earths and other metals.…”

“…Second, calixarenes are a versatile class of supramolecular compounds widely exploited as molecular platforms for the introduction of specic ligating arms in a reorganized pattern suitable for metal ions complexation. [1][2][3][4][5][6][7][8][24][25][26] Depending on the nature of the ligating groups, on the dimension of the macrocyclic scaffold and on the hydrophobicity, calixarenes have shown immense selectivity in the separation of alkaline and alkaline earth ions, 27 heavy metals 28 and f-elements. 1,29 The latter and the tunable shape of the molecules make them ideal candidates for building blocks and molecular scaffolds in the design of new and more sophisticated ligands.…”

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

“…values through the Ln series. Such opposite effects (gain in extraction efficiency but lower selectivity for synergistic mixtures along the Ln series, as compared to the acidic extractant used alone) are quite common in traditional molecular solvents [47][48][49] although in some cases, synergism also leads to better selectivity. 9 …”