Synthesis and characterization of new unsymmetrical diglycolamide extractants for lanthanide ion partitioning: part one—straight-chain alkyl derivatives

Six novel unsymmetrical diglycolamide (UDGA) ligands have been synthesized and evaluated as solvent extraction reagents for the partitioning of lanthanide (Ln) ions from nitrate media. The partitioning of europium between aqueous phases of varying nitric acid concentrations and a UDGA organic phase has been characterized radiometrically. The stoichiometry and phase-transfer equilibrium constants of the Eu-UDGA complexes extracted into the organic phase have been reported. Luminescence spectroscopy investigations have established the relative stability and stoichiometry of the complexes in acetonitrile. These UDGA ligands have displayed enhanced interfacial activity, which has decreased the necessary equilibration time while maintaining high Ln distribution ratios.