Solvent extraction of europium(III) and neodymium(III) with 4(p)-nitrobenzoyl-2, 4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one and neutral oxo-donors

The mechanism of the extraction of europium(III) and neodymium(III) from aqueous buffer media with 4(P)-nitrobenzoyl-2, 4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (NMPP) in toluene has been investigated. The value of log Kex(where Kex refers to the equilibrium M3++3HL ↔ ML3+3H+) is -1.4 and -1.6 for Eu and N d respectively, NMPP seems to be superior to the corresponding 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one and also better than thenoyltrifluoroacetone and hexafluoroacetylacetone. The effect of various types of Lewis bases in combination with NMPP on the extraction of EuIII and NdIII has also been studied. A large synergistic enhancement was 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 calculated. (author). 10 refs., 3 figs