Analytical Sciences

Abstract − Analytical Sciences, 30(3), 323 (2014).

Highly Selective Synergism for the Extraction of Lanthanoid(III) Ions with β-Diketones and Trioctylphosphine Oxide in an Ionic Liquid
Hiroyuki OKAMURA,*,** Hitomi TAKAGI,* Taku ISOMURA,* Kotaro MORITA,* Hirohisa NAGATANI,* and Hisanori IMURA*
* Faculty of Chemistry, Institute of Science and Engineering, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
**Division of Chemistry for Nuclear Engineering, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
Selective synergism for the extraction of lanthanoids(III) (Ln) with β-diketones such as 2-thenoyltrifluoroacetone, 2-naphthoyltrifluoroacetone, and benzoylacetone has been investigated in the presence of trioctylphosphine oxide as a hydrophobic neutral ligand in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide as an ionic liquid. The extractability of heavier Ln was remarkably enhanced, resulting in a significant improvement in the separation of Ln. It was found that the present synergism is ascribed to the formation of cationic ternary complexes, followed by ion exchange into the ionic liquid.