Effect of crown ethers on the solvent extraction and separation of lanthanide(III) ions with 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one

Synergistic solvent extraction of 14 lanthanides with mixtures of 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP) and the crown ethers (S), 18-crown-6, benzo-18-crown-6 or dibenzo-18-crown-6 from an aqueous chloride medium with the constant ionic strength of 0.1 mol dm(-3) was investigated using benzene as a diluent. The composition of the species extracted was determined as LnP3 center dot S. The addition of a crown ether to the chelating extractant produced rather significant synergistic effects. On basis of experimental data, values of equilibrium constants, synergistic coefficients, and separation factors were calculated. (c) 2008 Institute of Chemistry, Slovak Academy of Sciences.