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

ABSTRACT

The selective liquid-liquid extraction of various alkaline, alkaline-earth and transition metal cations from the aqueous phase to the organic phase was carried out by using diazo coupling calix[4]arenes [p-(4-n-butyl-phenylazo)calix[4]arene(Ll), p-(4-phenylazophenyl-azo)calix[4]arene(L2), p-(4-acetamlidazo)calix[4]arene(L5)], p-(N′-2-thiazol-2-ylsulphanyl-azo)calix(4]arene(L4) and p-(2-thiazolazo)calix[4]arene(L5)] and the phenol derivatives [2-((5-bromo-2-pyridylazo)-5-diethylaminophenol(L6) and (2-chloro-4-nitrophenylazo)-5-sec-butyl-2-phenol(L7)]. It was found that compounds LI - L6 showed some selectivity towards Ag⁺, Hg⁺ and Hg²⁺, while extractability of all cations was observed with compound L2 containing double diazo groups.