Stability Constants of Ca2+, Cu2+, Zn2+, UO22+ , Mn2+, Co2+ and Ni2+ Complexes of Tetraethyl p-tert-Butylcalix[4]arene Tetraacetate in Nitrobenzene Saturated with Water

Emanuel Makrlík,1,* Petr Vaňura2 and Pavel Selucký2

1 Faculty of Applied Sciences, University of West Bohemia, Husova 11, 306 14 Pilsen
2 Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
3 Nuclear Research Institute, 250 68 Řež, Czech Republic
* Corresponding author: E-mail: makrlik@centrum/sz

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+ = Ca2+, Cu2+, Zn2+, UO22+  , Mn2+, Co2+, Ni2+; 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 cation order Mn2+ < Co2+ < Cu2+ < Zn2+ < UO22+, Ni2+ < Ca2+.

Keywords: Divalent metal cations, calix[4]arene compound, strontium dicarbollylcobaltate, extraction and stability constants, water – nitrobenzene system