4-Acylbis(1-Phenyl-3-Methyl-5-Pyrazolones)as extractants for f-elements

The liquid-liquid extraction of early actinides such as thorium(IV)and uranium(VI) and trivalent lanthanoids such as neodymium(III),europium(lIl) and lutetium(lIl) from nitrate solutions was studied using 4sebacoylbis(1-phenyl-3-methyl-5-pyrazolone) (H2SP) and 4-dodecandioylbis(1-phenyl-3-methyl-5-pyrazolone) (H2DdP) in chloroform as extractants.
The results demonstrate that these metal ions are extracted into chloroform as Th(SPh, Th(DdP)2, U02(HSP)2, U02(HDdP)2, Ln(SP)(HSP)and Ln(DdP)(HDdP) with H2SP or H2DdP. The equilibrium constants of the above species were deduced by non-linear regression analysis. The results clearly highlight that thorium(IV) can be selectively separated from uranium(VI) and trivalent lanthanoids when extracted from 0.2 mol/dm3 nitric acid solutions using 4-acylbis(1-phenyl-3-methyl- 5-pyrazolones). Thorium(IV), uranium(VI) and lutetium(lIl) complexes of H2SP were synthesised and characterised by IR and 'H NMR spectral data to further
clarify the nature of the complexes.