1,2,4,5-Tetra(diphenylphosphihyl)benzene as Novel Effective Extractant for Actinides and Lanthanides

ABSTRACT

A novel polyfunctional neutral organophosphorus ligand 1,2,4,5-tetra(diphenylphosphihyl)-benzene I containing four Ph₂P(O)- groups fixed on the benzene platform was synthesized and studied as an extractant for U(VI), Th(IV) and lanthanides(III) ions from HNO₃ solutions. The influence of aqueous and organic phases on the extraction efficiency was elucidated. Stoichiometry of the extracted complexes was determined, and the equilibrium constants were calculated. The extraction efficiency of compound I towards U(VI)), Th(IV) and lanthanides(III) ions is significantly higher than that of its analogue V with methylene spacers between P(O) groups and a benzene ring. Compound I extracts U(VI) more effectively than tetraphenylmethylenediphosphine dioxide VIa, one of the most effective extractants of actinides and lanthanides from nitric acid solutions, but ranks below in the extraction of Th(IV) and Ln(III).

KEYWORDS:

• Extraction
• uranium(VI)
• thorium(IV)
• lanthanides(III)
• tetra(diphenylphosphihyl)benzene

Acknowledgments

The study was performed within the framework of the government assignment for the ISSP RAS, IMTHPM RAS and INEOS RAS and was financially supported by Ministry of Science and Higher Education of the Russian Federation using the equipment of Center for molecular composition studies of INEOS RAS.