A Study of the Purification and Acid-Base Behavior of the Commercial Extractants KELEX 100 and LIX 26

Several methods for the purification of the active components of the 8-hydroxyquinoline derivative commercial extractants KELEX 100 and LIX 26 have been studies. Among the different methods tried (washing with different solutions, formation of insoluble metal complexes, and column chromatography), the best performance was observed for column chromatography. The active components of KELEX 100 from Ashland (producer up to 1976) and from Sherex (producer from 1976) were characterized using IR, 1H NMR, 13C NMR, and mass spectrometry as 7-(1′-vinyl-3′,3′,5′,5′-tetramethylhexyl)-8-hydroxyquinoline and 7-(1′-methyl-4′-ethyloctyl)-8-hydroxyquinoline, respectively. In the case of LIX 26, a TLC “pure” fraction was isolated and characterized as a 7-alkyl substituted (∼ 14 carbon) derivative of 8-hydroxyquinoline that could not be fully resolved. A study of the acid–base properties of the active components of the extractants has also been carried out, and their acidity constants have been calculated by means...