Ionic Liquid Chelate Extraction Behavior of Trivalent Group 13 Metals into 1-Alkyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imides Using 8-Quinolinol as Chelating Extractant.

Ionic liquid (IL) chelate extraction behavior of trivalent Group 13 metals including aluminum(III), gallium(III) and indium(III) with 8-quinolinol (HQ) was investigated using three 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (CmimTfN, n = 2, 4 and 8) ILs. Although the three extraction systems showed similar extraction selectivity among the metals, the extractability order for the metals among the extraction systems was CmimTfN > CmimTfN > CmimTfN, which was the same as the order of hydrophobicity in the IL cation. Only the neutral 1:3 complex species was extracted in use of more-hydrophobic CmimTfN, whereas use of less-hydrophobic CmimTfN and CmimTfN resulted in competitive extraction of neutral 1:3 and cationic 1:2 complexes.

Extraction Ability of 4-Benzoyl-3-phenyl-5-isoxazolone towards 4f-Ions into Ionic and Molecular Media.

The distribution constants of 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) and deprotonated one (PBI) between hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([CCim][TfN]) and aqueous phases were determined, together with the acid-dissociation constant of HPBI. The solvent extraction of three selected lanthanoid ions (La, Eu, and Lu) with HPBI from aqueous nitrate phase into [CCim][TfN] has been investigated. Application of the ionic liquid as the extracting phase greatly enhanced the extraction performance of HPBI for lanthanoid ions compared with that in the chloroform system.

Distribution Equilibria of Amphoteric 8-Quinolinol between 1-Alkyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide and Aqueous Phases and Their Effect on Ionic Liquid Chelate Extraction Behavior of Iron(III).

The distribution behavior of amphoteric 8-quinolinol (HQ) between ionic liquid (IL) phase and aqueous phase and ionic liquid chelate extraction behavior of iron(III) with HQ were investigated using four 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (CmimTfN, n = 2, 4, 6 and 8) ILs. Not only neutral HQ but also cationic HQ were distributed into the IL phase, and the latter distribution based on cation-exchange with Cmim was pronounced in the use of IL having a less-hydrophobic cation, such as Cmim. In the IL chelate extraction of iron(III), the extractability increased with the increase in the hydrophobicity of IL as the extraction phase.