Phosphoryl-containing acidic podands as extractants for recovery of f-elements: 2. Synthesis and comparison of podands different in terminal group structure

The properties of a number of phosphoryl-containing acidic podands different in terminal group structure were compared in the extraction of uranium(vi), thorium(iv), lanthanum(iii), neodymium(III), holmium(III), and ytterbium(III) from nitric acid solutions to 1,2-dichloroethane: 2-[(HO)(RO)(O)P]-4-R´-C6H4–(OCH2CH2)2–OC6H4–4-R´-2-[P(O)(RO)(OH)] (1–6), where R = Et, R´ = H (1), R = Bu, R´ = H (2), R = R´ = Et (3), R = Bu, R´ = Et (4), R = Et, R´ = But (5), and R = Bu, R´ = But (6). The synthesis of podands 2, 4, and 6 obtained for the first time was described. The most efficient extractants for selective recovery of ThIV and UVI in the presence of lanthanides are podands 4–6, which extract actinides quantitatively at low concentrations of nitric acid. Micellar aggregates 6–90, 7–70, and 9–20 nm in size were found by the dynamic light scattering method in extracts of uranium(vi), thorium(iv), and neodymium(iii), respectively, by podand 4. The composition and structure of extracted uranium complexes were determined for podand 2 by IR spectroscopy and elemental analysis.