EXTRACTION STUDIES OF AM(III) AND EU(III) WITH A TRIS-BIPYRIDYL MACROBICYCLIC LIGAND

Complexation of Am(III) with a tris-bipyridine cryptand (L) has been c arried out in a nonaqueous medium (CH3CN-CHCl3). Subsequently the comp lexation behaviour was investigated using the reverse extraction trace r technique with dinonyl naphthalenesulphonic acid (HD) in toluene as the organic phase and varying concentration of HCI (upto 2M) as the aq ueous phase. Equilibrium is attained in the two-phase system at a rate dependent on the hydrogen ion concentration in the aqueous phase. Whe reas it takes only a few minutes to attain the equilibrium state at pH 6.0, a phase contact period of 50 days was insufficient if the acidit y is greater than 0.4M, presumably due to the slow dissociation of the cryptate formed. The large enhancement in the distribution ratio valu e in the synergistic system with 1 M HCI as the aqueous phase under no n-equilibrium conditions is employed for the analytical separation of Am(III) from Eu(III).