Solvent extraction of barium picrate by p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide)

From extraction experiments and gamma-activity measurements, the extraction constant of the Ba2+(aq)+2A-(aq)+L(nb)double left right arrow Bal(2+)(nb)+2A(-)(nb) equilibrium in the two-phase water-nitrobenzene system (L = p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as logK(ex)(BaL2+,2A(-)) = 6.5 +/- 0.1. Furthermore, the stability constant of the p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide)-barium complex in nitrobenzene saturated with water was calculated for at 25 degrees C: s log beta(nb)(Bal(2+)) = 15.4 +/- 0.1.