Effect of Benzyltriethylammonium Di-2-ethylhexyl Sulfosuccinate on the Extraction of Lanthanides(III) from Nitric Acid Solutions with Bis(diphenylphosphorylmethylcarbonylamino)alkanes

The efficiency of the lanthanide(III) extraction from nitric acid solutions with bis(diphenylphosphorylmethylcarbonylamino)alkane (bis-CMPO) solutions in organic solvents significantly increases in the presence of an ionic liquid, benzyltriethylammonium di-2-ethylhexyl sulfosuccinate ([N222Bn]SSu), in the organic phase. The lanthanide(III) distribution ratios in the extraction from 3 M HNO3 solution with bis-CMPO solutions in dichloroethane increased by more than two orders of magnitude in the presence of [N222Bn]SSu. Lanthanide(III) ions are extracted with mixtures of bis-CMPO and the ionic liquid in organic solvents via the cation-exchange mechanism. The influence of the structure of bis-carbamoylmethylphosphine oxides, kind of organic diluent, and HNO3 concentration in the aqueous phase on the efficiency of the metal ion extraction into the organic phase containing the ionic liquid is discussed.