Highly Selective Solvent Extraction of Copper(II) from Transition Metal Ions with Dibutyl N,N′-Bis(8-quinolyl)malonamide

Abstract
Dibutyl-N,N′-bis(8-quinolyl)malonamide can extract only Cu(II) with excellent selectivity among Cu(II), Ni(II), Co(II), and Zn(II) both in the competitive and single metal ion-extraction. It forms 1 : 1 complex with Cu(II) ion accompanied with the release of two protons from the amide groups.