Five lanthanoid ions were extracted with 3-methyl-1-phenyl-4-(4-trifluoromethylbenzoyl)-pyrazol-5-one alone and in combination with partially substituted calix[4]arenes as synergistic agents using CHCl3 and one IL.

No abstract

No abstract

Aqueous-ionic liquid (A-IL) biphasic systems have been examined in terms of deuterated water, acid, and IL cation and anion mutual solubilities in the upper (water-rich, in mole fraction) and lower phase of aqueous/IL biphasic systems at ambient temperature. The biphasic mixtures were composed of deuterated acids of various concentrations (mainly DCl, DNO(3), and DClO(4) from 10(-2) to 10(-4)  M) and five ionic liquids of the imidazolium family with a hydrophobic anion (CF(3)SO(2))(2) N(-), that is, [C1 Cn im][Tf(2)N], (n=2, 4, 6, 8 and 10). The analytical techniques applied were (1) H NMR, (19) F NMR, Karl-Fischer titration, pH potentiometry for IL cations and anions, and water and acid determination. The effects of the ionic strength (μ=0.1 M NaCl and NaNO(3) as well as μ=0.1 M, 0.2 M and 0.4 M NaClO(4), according to the investigated acid), the nature of the IL cation, and the nature of the mineral acid on the solubilities of the (D(2)O, D(+), Tf(2)N(-), C1 Cn im(+)) entities in the lower or upper phases were determined. The addition of sodium perchlorate was found to enhance the Tf(2)N(-) solubility while inhibiting the solubility of the ionic liquid cation. Differences in IL cation and anion solubilities of up to 42 mM were evidenced. The consequences for the characterization of the aqueous biphasic system, the solvent extraction process of the metal ions, and the ecological impact of the ILs are discussed.

No abstract

The study of trivalent lanthanoid (La, Nd, Eu, Ho and Lu) extraction by two individual ligands: one acidic as pyrazolone derivative, 3-methyl-1-phenyl-4-(4-phenylbenzoyl)-pyrazol-5-one (HL), and one neutral as 5,11,17,23-tetratert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene (SIV) was performed in CHCl3 and in one ionic liquid, IL (1-methyl-1,3butylimidazolium-bis(trifluoromethanesulfonyl)imide ([C1C4im][Tf2N]) in order to establish and examine the impact of the diluent onto the individual and synergistic extraction processes. Chloride aqueous medium and constant ionic strength μ = 0.1 M were set in both cases. The parameters of the extraction processes were determined. Comparison between the two diluents was made on the basis of: i) Composition of the extracted species: LnL3·HL in CHCl3 vs LnL3 in IL with HL as a single extractant (L − represents the HL anion), and LnL3·SIV in the presence of the phosphorus-containing calix[4]arene in both diluents; and ii) Values of the equilibrium constants and the synergistic enhancements; the separation factors between metals were evaluated as well.The IL medium appears far superior to the molecular solvent in terms of individual and overall synergistic extraction efficiencies. However, the huge differences in extraction efficiencies observed in CHCl3 for chemically different ligands are erased in the IL medium, thus modifying the lever arms on which chemists should rely in order to obtain even better extracting systems in ionic liquid media.

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

No abstract