Solvent Extraction of Europium and Americium into Nitrobenzene by Using Hydrogen Dicarbollylcobaltate in the Presence of 3,3′-Bis(diphenoxyphosphoryl)-1,1′-(heptane-1,7-diyl)diurea

Abstract

Solvent extraction of micro amounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of 3,3′-bis(diphenoxyphosphoryl)-1,1′-(heptane-1,7-diyl)diurea (L) was investigated. The equilibrium data were explained assuming that the species HL⁺, ML³⁺, and ${\text{ML}}_{2}^{3 + }$ (M³⁺ = Eu³⁺, Am³⁺; L = 3,3′-bis(diphenoxyphosphoryl)-1,1′-(heptane-1,7-diyl)diurea) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species were determined in nitrobenzene saturated with water. It was found that the values of the stability constants of the corresponding complexes $\text{EuL}_{n}^{{\text{3} + }}$ and $\text{AmL}_{n}^{{\text{3} + }}$, where n = 1, 2 and L is 3,3′-bis(diphenoxyphosphoryl)-1,1′-(heptane-1,7-diyl)diurea, in water-saturated nitrobenzene are comparable. Finally, it was proven experimentally that in the nitrobenzene medium, the 3,3′-bis(diphenoxyphosphoryl)-1,1′-(heptane-1,7-diyl)diurea ligand is a very effective receptor for the Eu³⁺ and Am³⁺ cations.

Graphical Abstract