Solvent Extraction of Ba2+, Pb2+ and Cd2+ into Nitrobenzene by Using Strontium Dicarbollylcobaltate in the Presence of Tetraethyl p-tert-Butylcalix[4]arene Tetraacetate

Emanuel Makrlík,a,* Petr Vaňurab and Pavel Seluckýc

a Faculty of Applied Sciences, University of West Bohemia, Husova 11, 306 14 Pilsen, Czech Republic.
b Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic
c Nuclear Research Institute, 250 68 Řež, Czech Republic
* Corresponding author: E-mail:

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+(aq) + SrL2+(nb) ML2+(nb) + Sr2+(aq) taking place in the two-phase water-nitrobenzene system (M2+ = Ba2+, Pb2+, Cd2+; L = tetraethyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Ba2+ < Cd2+ < Pb2+.

Keywords: Barium, lead, cadmium, strontium dicarbollylcobaltate, nitrobenzene, calix[4]arene, extraction and stability constants