Extraction of trivalent lanthanoids into ionic liquids having different side chain lengths in anions

Eguchi, Ayano ; Okamura, Hiroyuki   ; Sugita, Tsuyoshi   ; Ueda, Yuki   ; Morita, Kotaro*; Shimojo, Kojiro   ; Naganawa, Hirochika  ; Hirayama, Naoki*

In this study, the effect of the perfluoroalkyl (Rf) chain length of the ionic liquid (IL) anion on the IL chelate extraction was investigated. Four 1-butyl-3-methylimidazolium bis(perfluoroalkanesulfonyl)imides with different Rf chain length (n = 1 - 4) were synthesized and used as extraction solvents. Herein, the extraction of trivalent lanthanoids (Ln(III) = La, Nd, Eu, Dy and Lu) with an extractant, 2-thenoyltrifluoroacetone, was studied. It was revealed that the extracted complex depends on even or odd number of the Rf chain length n.