LIQUID-LIQUID-EXTRACTION OF TRANSITION-METAL CATIONS BY DIAZO COUPLING CALIX[4]ARENE DERIVATIVES

The selective liquid-liquid extraction of various alkaline, alkaline-e arth and transition metal cations from the aqueous phase to the organi c phase was carried out by using diazo coupling calix[4]arenes [p-(4-n -butyl-phenylazo)calix[4] arene(L1), p-(4-phenylazophenylazo)calix[4]a rene(L2), p-(4-acetanilidazo)calix[4]arene(L3), p-(N'-2-thiazol-2-ylsu lphanylazo)calix[4]arene(L4) and p-(2-thiazolazo)calix[4]arene(L5)] an d the phenol derivatives 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (L7)] and hloro-4-nitrophenylazo)-5-sec-butyl-2-phenol(L7)]. It was fo und that compounds L1 - L6 showed some selectivity towards Ag+, Hg+ an d Hg2+, while extractability of all cations was observed with compound L2 containing double diazo groups.