Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

A series of N,N,N-trialkyl-2-(hydroxyimino)-2-(pyridin-2-yl)ethan-1-aminium nitrates 3a-3h and N,N,N-trialkyl-4-(hydroxyimino)-4-(pyridin-2-yl)butan-1-aminium nitrates 3i-3l representing cationic surfactants with a powerful 1-(hydroxyimino)-1-(pyridin-2-yl)alkyl chelating subunit were prepared as potential selective metal ion extractants. Their extraction ability was tested in transport of Cu²⁺, Ni²⁺, Co²⁺, and Pd²⁺ through a bulk liquid membrane. The introduction of the cationic group into the extractant molecule increases the selectivity and facilitates the metal ion transport as shown by comparing the transports carried out with ligand surfactants 3 and lipophilic alkyl pyridin-2-yl ketoximes 2. The efficiency and selectivity of the metal ion transport mediated by ligand surfactants 3 depends predominantly on their structure and lipophilicity, i.e. on the number and length of hydrophobic alkyl chains and on the length of the spacer connecting the chelating moiety with the cationic head group of the surfactant.

Keywords: Ligands; Liquid membranes; Metal ion transport; Oximes; Pyridine derivatives; Surfactants; Copper; Palladium; Quaternary ammonium salts; Extractions.

References: 64 live references.