Extraction of NH4+, K+, Rb+ and Tl+ into nitrobenzene using cesium dicarbollylcobaltate in the presence of dibenzo-21-crown-7

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq) + CsL+(nb) ↔ ML+(nb) + Cs+(aq) taking place in the two-phase water-nitrobenzene system (M+ = NH4+, K+, Rb+, Tl+; L dibenzo-21-crown-7; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Cs+<K+ = Rb+ ∼ NH4+<Tl+. (author)