DISTRIBUTION EQUILIBRIUM OF LANTHANIDE(III) COMPLEXES WITH N-BENZOYL-N-PHENYLHYDROXYLAMINE IN SEVERAL INERT SOLVENT SYSTEMS
ABSTRACT The distribution equilibrium of lanthanides(III) (Ln) with N-benzoyl-N-phenylhydroxylamine (BPHA, HL) in several inert solvent systems was studied. The representative lanthanides(III) (Yb, Eu and Pr) were all found to extract as self-adduct chelates of the form, LnL3(HL)m, (m = 1–3), containing a different number of neutral adduct molecules in extracted species. The differences in the number of neutral adduct molecules in extracted species with each solvents are attributed to the difference in the solvation trend for BPHA. The extraction constant and separation factor were determined in several inert solvent systems. It was found that the distribution ratio of lanthanide(III) tends to decrease with increases in the distribution constant of BPHA. Relationship between the polarity of the solvent and the extractability are also discussed.