Synergistic Solvent Extraction of Trivalent Lanthanides With Mixtures of 3-Phenyl-4-Benzoyl-5-Isoxazolone and Crown Ethers

Synergistic solvent extraction of trivalent lanthanides such as Nd, Eu and Tm has been studied using mixtures of 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) and 18-crown-6; 15-crown-5, benzo-15-crown-5, or dibenzo-18-crown-6. The results demonstrate that these trivalent metal ions are extracted into chloroform as Ln(PBI)3 with HPBI alone and as Ln(PBI) 3. CE in the presence of crown ethers (CE). The equilibrium constants of the above species are found to increase monotonically with the decreasing ionic radii of these trivalent lanthanides. The addition of a crown ether to the metal chelate system significantly enhances the extractability of these trivalent metal ions.