Solvent extraction of metal ions with mixed ligands—IV: Extraction of Eu(III) with chelating acids and neutral adduct-forming ligands

Abstract

The distribution of Eu(III) has been studied with various mixtures of ligands. The following results have been obtained. 1. (a) The addition of 0·1 M tributylphosphate (TBP) shifted the distribution ratio of Eu(III) between chloroform with various chelating acids and 0·1 M (H, Na)ClO 4. The shifts (given as log DD 0 −1) for the different chelating acids were: 2-thenoyltrifluoroacetone (+ 3·4), 1-naphtholic acid (+1·1), β-isopropyltropolone (+0·5), 5,7-dichloro-oxine (+0·4), N-benzoylphenylhydroxylamine (no shift), dioctylphosphate (−0·3) and N-2,4-dichlorobenzoylphenylhydroxylamine (−0·4). 2. (b) The extraction of the europium(III)-TTA chelate into chloroform and carbon tetrachloride was increased by the addition of the following ligands: trioctylphosphine oxide > tributylphosphate > quinoline > coumarin > hexone > α-napthol. The adduct formation constants for EuA 3L and in some cases EuA 3L 2 were obtained graphically and are summarized in Table 2. The formation constants are larger in carbon tetrachloride than in chloroform. 3. (c) An increase in the distribution of Eu(III) was also observed by the addition of other chelating acids to 0·1 M TTA in chloroform (Fig. 3).