Extraction of Uranium(VI), Thorium(IV), and Trivalent Rare Earths from Nitric Acid Solutions with {[2-(2-Diphenylphosphoryl)-4-ethylphenoxy]ethyl}diphenylphosphine Oxide

A new extractant, {[2-(2-diphenylphosphoryl)-4-ethylphenoxy]ethyl}diphenylphosphine oxide, has been synthesized, and its solutions in 1,2-dichloroethane and a ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, have been used to extract HNO 3 , uranium(VI), thorium(IV), and trivalent rare earths from nitric acid solutions. The stoichiometry of the extracted complexes has been determined, and the effects of the extractant structure and HNO 3 concentration in the aqueous phase on the extraction efficiency have been studied. The extraction efficiency has been found to significantly increase when ionic liquid is present in the organic phase.