Synthesis and evaluation of novel water-soluble ligands for the complexation of metals during the partitioning of actinides?

New Journal of Chemistry Pub Date: 2011-09-06 DOI: 10.1039/C1NJ20523D

Abstract

Different types of water-soluble ligands were synthesized and their capability was evaluated by solvent extraction studies to complex trivalent actinides and suppress their extraction by a strong lipophilic ligand, such as TODGA. The back extraction efficiency of hydrophilic diglycolamide (DGA) derivatives with a varying number of ethylene glycol groups, or containing sodium acetate moieties on the amidic nitrogen shows a decrease in back-extraction efficiency with increasing number of ethylene glycol units on the amidic nitrogen at various pH values of the aqueous phase. Among the P[double bond, length as m-dash]S donating ligands only the ligand with a malonamide backbone exhibits a high reverse extraction efficiency, although, with no selectivity for americium. Within the water-soluble tripodal ligands, i.e. the amide derivatives of nitrilotriacid with N,N-dimethyl and N,N-bis(hydroxyethyl) moieties, the first one shows a pronounced selectivity for Am(III) over Eu(III), with a maximum separation factor of 11.1, while the latter one more efficiently complexes the radionuclides in the aqueous phase with a maximum separation factor of 5. Isothermal microcalorimetry experiments of the complexation of Eu(III) by a selected series of ligands confirm the observed trend in the back extraction properties.

Graphical abstract: Synthesis and evaluation of novel water-soluble ligands for the complexation of metals during the partitioning of actinides
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