Extraction of Rare-Earth Elements(III) from Nitric Acid Solutions with Diethyl 2-[(Diphenylphosphoryl)methoxy]-5-ethylphenylphosphonate

Abstract

Extraction of micro amounts of rare earth elements(III) (REE) from nitric acid solutions with diethyl 2-[(diphenylphosphoryl)methoxy]-5-ethylphenylphosphonate (I) in dichloroethane and ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide has been studied. The stoichiometry of extracted complexes has been determined, the effect of HNO₃ concentration in aqueous phase on the efficiency of metal ion recovery into organic phase has been considered. It has been found that compound I in dichloroethane extracts REE(III) less efficiently than its analogs with phenyl and butyl substituents at the phosphorus atom. It has been shown that the efficiency of REE(III) extraction with compound I from nitric acid solutions increases considerably in the presence of ionic liquid in organic phase.