THE EXTRACTION OF LANTHANIDES WITH HALOGEN SUBSTITUTED 4-ACYL-PYRAZOLONES

Abstract
Equilibrium extraction behavior for a series of representative tervalent lanthanide ions, La, Pr, Eu, and Yb, using chloroform solutions containing halogenated derivatives of 4-acyl-l-phenyl-3-methyl-5-pyrazolone have been studied. The results demonstrate that these lanthanides are extracted as simple chelates, LnL⊂3⊂. The equilibrium constants of these extraction reactions have been calculated. The relationships between the acid dissociation constants, K⊂a⊂, determined by a two-phase titration method, distribution constants, K⊂DR⊂, and the extraction equilibrium constants, K⊂ex⊂, discussed.