Solvent Extraction of Several Trivalent Metal Ions with 4-Isopropyltropolone into Chloroform

Abstract

The solvent extraction of lanthanum(III), praseodymium(III). neodymium(III), samarium(III), europium(III), gadolinium(III), thulium(III), ytterbium(III), lutetium(III), scandium(III), and indium(III) (M(III)) in 0. mol dm 3 sodium nitrate solutions with 4-isopropyltropolone (Hipt) into chloroform was studied. From the dependence of extraction on the concentration of 4-isopropyltropolonate anions in the aqueous phase and also on the concentration of metal ions, it was concluded that scandium(III) and indium(III) were always extracted in the mononuclear form, M(ipt) 3 , But dinuclear lanthanoid(III) chelate complexes, M 2 (ipt) 6 nHipt where n=0 or 1, were also extracted with mononuclear ones even when the metal concentration in the organic phase was higher than about 10 -6 mol dm -3 . The degree of dinuclear species formation was greater in the following order: lutetium(III) to samarium(III)>neodymium(III)>praseodymium(III)>lanthanum(III) scandium(III) - indium(III). On the other hand, the stability of the self-adduct dinuclear chelate complexes in the organic phase was higher in the order: lanthanum(III) to gadolinium(III)>thulium( III)>ytterbium(III )>lutetium(III).