Extraction of REE(III), U(VI), and Th(IV) with Bis[ N -alkyl- N -(2-diphenylphosphinylethyl)]diglycolamides from Nitric Acid Solutions

Extraction ability of modified phosphoryl-containing diglycolamides [Ph 2 P(O)CH 2 CH 2 N(R)C(O)CH 2 ] 2 O (R = Me, Bu, Oct) toward U(VI), Th(IV), and REE(III) ions in organic solvents from nitric acid solutions has been studied. Dependence of extraction efficiency on extractant structure, solvent nature, composition of organic and aqueous media, and the stoichiometry of recovered complexes has been considered. It has been shown that the studied diglycolamides containing acceptor P=O groups in the amide fragments of molecule extract U(VI) more efficiently but Th(IV) and REE(III) less efficiently (as compared with the known extractant tetraoctyldiglycolamide).