Extraction of Lanthanides(III) from Nitric Acid Solutions with Tetraphenylmethylenediphosphine in the Presence of Bis[(trifluoromethyl)sulfonyl]imides of Quaternary Ammonium Bases

The interphase distribution of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu between aqueous HNO3 solutions and solutions of tetraphenylmethylenediphosphine dioxide in 1,2-dichloroethane was studied. The latter solutions also contained ionic liquids with an anion of bis[(trifluoromethyl)sulfonyl]imide and cations of quaternary ammonium bases. It was detected that the extraction of metal ions significantly increases in the presence of ionic liquids in the organic phase. The stoichiometry of the extracted complexes was determined, and analysis was made of the effect of the HNO3 concentration in the aqueous phase and the nature of the cationic part of an ionic liquid on the efficiency of the extraction of metal ions into the organic phase.