Synergistic extraction of erbium(IIl) with 1-phenyl-3-methyl-4-<i>p</i>-nitrobenzoyl-5-pyrazolone and 3-phelyl-4-benzoyl-5-isoxazolone using neutral oxodonors

Abstract

Two different types of β-diketones, 1-phenyl-3-methyl- 4-<i>p</i>-nitrobenzoyl-5-pyrazoloneI (NMPP) and 3-phenyl- 4-benzoyl-5-isoxazolone (HPBI) have been employed for the solvent extraction of erbiun(III) from aqueous buffer media into toluene. The value of log <i>K</i>_ex, where <i>K</i>_ex refers to the equilibrium, Er(III) + 3HL <img src='http://www.niscair.res.in/jinfo/harpoon.gif' border=0> ErL₃ + 3H⁺ is - 1.1 and + 0.9 for Er-NMPP and Er-HPBI respectively. The effect of various lewis bases, viz., tri-<i>n</i>-octyl-phosphine oxide (TOPO), tri-<i>n</i>-butyl phosphafe (TBP) and dibenzyl sulphoxide (DBSO) in combination with NMPP and HPBI respectively on the extraction of Er(III) has also been studied. A large synergistic enhancement has been observed in both the cases with all the lewis bases. Synergistic extraction constants, stability constants, and the stoichiometry of the respective adducts formed during the extraction have been determined.