Neutral bidentate N-heterocyclic ligands – phase transfer reagents improving the kinetics of solvent extraction of Am(III) and Eu(III) ions with tetradentate 6,6′-bis-(diethyl-1,2,4-triazin-3-yl)-2,2′-bipyridine

Abstract

Poor kinetics of solvent extraction of Am(III) and Eu(III) ions from 1 M HNO3 with 6,6′-bis-(diethyl-1,2,4-triazin-3-yl)-2,2′-bipyridine (etBTBP) has been improved by adding an auxiliary bidentate N-heterocyclic ligand to the extraction system. Two such ligands were studied, derivatives of bis-triazine and pyridine-triazine, which alone poorly extract the metal ions, but together with etBTBP they act as phase transfer reagents, improving the extraction kinetics to a different degree. The ability to transfer the metal ions from aqueous to organic phase depends on lipophilicity and acid/base properties of these auxiliary ligands, as well as on the mode of shaking the two liquid phases — gentle or vigorous.