SYNERGIC SOLVENT EXTRACTION OF EUROPIUM(3) INTO MIXTURES OF 2-THENOYL-TRIFLUOROACETONE WITH VARIOUS ALKYLPHOSPHINE OXIDES

The synergic solvent extraction of tracer europium(III) from chloride medium into mixtures of thenoyltrifluoroacetone (HTTA) with methylenebis(di-n-hexylphosphine oxide), MHDPO; trimethylenebis(di-n-hexylphosphine oxide), PHDPO; tetramethylenebis(di-n-hexylphosphine oxide), BHDPO; or tri-n-octylphosphine oxide, TOPO, in cyclohexane was studied. The europium-containing species in the organic phase were shown to be Eu(TTA)3(TOPO)2, Eu(TTA)3(TOPO)2, Eu(TTA)3(MHDPO), Eu(TTA)3(PHDPO), and Eu(TTA)3(BHDPO). A solvent extraction-molar ration study using an acetate aqueous medium confirmed these stoichiometries and showed the formation of Eu(TTA)3(TOPO). The formation of Eu(TTA)3(TOPO) was confirmed with a loading capacity study. The synergic solvent extraction of tracer europium(III) from perchlorate medium into mixtures of HTTA and TOPO or HTTA and MHDPO in cyclohexane was also studied. The europium-containing species in the organic phase were shown to be Eu(TTA)3(TOPO)2 and Eu(TTA)-(ClO4)2(MHDPO)3. Equilibrium constants for the formation of all of the above complexes were calculated. © 1969.