Extraction Behavior of Metal Cations in Ionic Liquid Chelate Extraction System

• Hirayama Naoki

  Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University

Bibliographic Information

Other Title

• イオン液体キレート抽出系における金属イオンの抽出挙動
• イオン エキタイ キレート チュウシュツケイ ニ オケル キンゾク イオン ノ チュウシュツ キョドウ

Abstract

An "ionic liquid chelate extraction system", which is a novel liquid-liquid extraction method for the extractive separation of metal cations into the ionic liquid extraction phase with a chelate extractant, was investigated mainly from the point of difference from a normal chelate extraction system using a volatile organic solvent as the extraction phase. In this system, the extracted metals are easily recoverd by using back-extraction into an acidic solution. In the extraction of divalent metal cations (M²⁺) with 2-thenoyltrifluoroacetone (Htta) (or other β-diketone having trifluoromethyl group), some metals were extracted into the 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) extraction phase as coordination-unsaturated (hydrated) neutral complexes (M(tta)₂(H₂O)_n), whereas others were extracted as coordination-saturated anionic complexes (M(tta)₃⁻) with anion-exchange reactions. The extractability of the former species was reduced by using a more hydrophilic ionic liquid as the extraction phase, whereas that of the latter was enhanced. On the contrary, the use of 8-hydroxyquinoline (Hq) (or its derivative) as the extractant resulted in the extraction of M²⁺ into [bmim][PF₆] as neutral M(q)₂(H₂O)_n. Furthermore, a comparison of the extraction behavior of M²⁺ with 8-(trifluoromethanesulfonamido) quinoline (H(CF₃)sq) having a trifluoromethyl group with that with 8-(methanesulfonamido) quinoline (H(CH₃)sq) suggested that the existence of a trifluoromethyl group in an chelate extractant contributes to an enhancement of the extractability for an anionic complex into the ionic liquid extraction phase. In addition, a fundamental study was performed on an ionic liquid synergistic cation-exchange extraction system with co-using Htta and 18-crown-6 (18C6) as extractants for the selective extraction of trivalent light lanthanoids, such as lanthanum (La). In this system, La³⁺ was extracted into 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide as cationic ternary complexes, such as La(tta)₂(18C6)⁺ and La(tta)(18C6)²⁺.

Journal

• BUNSEKI KAGAKU

  BUNSEKI KAGAKU 57 (12), 949-959, 2008

  The Japan Society for Analytical Chemistry

Keywords

• ionic liquid chelate extraction system
• ionic liquid
• hydrated neutral complex
• anionic complex

Details

• CRID: 1390001204356016512
• NII Article ID: 110007008603
• NII Book ID: AN00222633
• DOI: 10.2116/bunsekikagaku.57.949
• COI: 1:CAS:528:DC%2BD1MXhtFWjsQ%3D%3D
• NDL BIB ID: 9746298
• ISSN: 05251931
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I9746298
• Web Site: http://www.jstage.jst.go.jp/article/bunsekikagaku/57/12/57_12_949/_pdf
• Web Site: http://dl.ndl.go.jp/info:ndljp/pid/10897127
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • NDL-Digital
  • CiNii Articles
• Abstract License Flag: Disallowed