• Home
  • Search Results
  • Cation and anion selectivity of zwitterionic salicylaldoxime metal salt extractants.

Cation and anion selectivity of zwitterionic salicylaldoxime metal salt extractants.

Dalton transactions (Cambridge, England : 2003) (2010-05-08)
Ross S Forgan, James E Davidson, Francesca P A Fabbiani, Stuart G Galbraith, David K Henderson, Stephen A Moggach, Simon Parsons, Peter A Tasker, Fraser J White
ABSTRACT

3-Dialkylaminomethyl substituted salicylaldoximes are efficient metal salt extractants, and, in contrast to related "salen"-based reagents, are sufficiently stable to acid hydrolysis to allow commercial application in base metal recovery. Crystal structures show that metal salts are bound by a zwitterionic form of the reagents, with copper(II) nitrate, tetrafluoroborate and trifluoroacetate forming [Cu()(2)X(2)] assemblies in a tritopic arrangement with a trans-disposition of the anions outwith the coordination sphere. Copper(II) chloride, bromide and zinc(II) chloride form 1:1 assemblies, [Cu()X(2)], with the halides in the inner coordination sphere of the metal, leading to high chloride selectivity and very good mass transport efficiencies of CuCl(2). Introduction of the anion-binding sites into the salicylaldoxime extractants changes their cation selectivities; the ligands co-extract small amounts of Fe(III) along with Cu(II) from mixed metal aqueous feed solutions, an issue which will need to be addressed prior to industrial application.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Salicylaldoxime, ≥98.0% (NT)