SOLVENT EXTRACTION OF ALKALI METAL PICRATES BY BENZO-15-CROWN-5.

Benzo-15-crown-5 (B15C5) extracted alkali metal picrates (MA) into benzene by forming M(B15C5)A or M(B15C5)//2A complexes and moreover, in the presence of tributyl phosphate (B), B15C5 extracted rubidium and cesium picrates by forming M(B15C5)BA complexes. The extractability sequences of the M(B15C5)A, MM(B15C5)//2A, and M(B15C5)BA complexes are Na** plus greater than K** plus greater than Rb** plus greater than Li** plus greater than Cs** plus , K** plus greater than Rb** plus greater than Cs** plus , and Rb** plus greater than Cs** plus respectively. The extraction equilibrium constants for these complexes have been determined at 25 degree C, and the synergistic formation constants of the M(B15C5)//2A and M(B15C5)BA complexes in the benzene solution have been calculated. The synergistic effects for the alkali metal ions for the B15C5 system were compared with those for the 15C5 system.