Stability Constants of Some Univalent Cation Complexes of Tetra-tert-butyl p-tert-Butylcalix[4]arene Tetraacetate in Nitrobenzene Saturated with Water

Emanuel Makrlík,1,* Jan Budka2 and Petr Vaňura2

1 Faculty of Applied Sciences, University of West Bohemia, Husova 11, 306 14 Pilsen, Czech Republic
2 Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic
* Corresponding author: E-mail:

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + NaL+ (nb) ML+ (nb) + Na+ (aq) taking place in the two–phase water–nitrobenzene system (M+ = Li+, NH+ 4, Ag+, K+ Rb+, Tl+, Cs+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; 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 series Cs+<Rb+ < Tl+ < K+ < NH+ 4 < Ag+ < Li+ .

Keywords: Univalent cations, calix[4]arene, water-nitrobenzene system, extraction and stability constants