Extraction of divalent metal cations into nitrobenzene in the presence of commercially available magnesium ionophores and substituted cyclic bis urea

The extraction of divalent cations (Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Pb 2+ , Cu 2+ , Zn 2+ , Cd 2+ , UO 2 2+ , Mn 2+ , Co 2+ , and Ni 2+ ) in the system water – nitrobenzene in the presence of magnesium ionophores and cyclic bis urea ([1,10-diaza-18-crown-6][C(O)NH(PO(O-isopropyl) 2 ] 2 )) (abbr. L) has been investigated. The stability constants of the complexes SrL 2+ have been determined from the extraction strontium picrate by the nitrobenzene solution of the ligands. The stability constants of other divalent cations have been determined from the competitive extraction in the systems water salt-divalent cation nitrate – ligand – nitrobenzene solution of strontium salt of dicarbollylcobaltate anion. It has been found that all ligands investigated have high affinity for all divalent metals investigated and the highest affinity for uranyl cation UO 2 2+ .