PREPARATION AND PROPERTIES OF CHELATING ION-EXCHANGERS WITH QUINALDIC ACIDS AS COMPLEXING GROUPS - INFLUENCE OF THE STRUCTURE OF THE COORDINATING LIGANDS ON THE COMPLEXING PROPERTIES

Quinoline-2-carboxylic acids with different substituents in the 4- and 8-positions of the quinoline ring have been grafted onto styrene-divinylbenzene polymers and tested for their ability to extract metal ions from aqueous sulfate solutions at low pH values. The position and nature of the substituents were found to play a major role in the metal ion selectivities, whereas the nature of the polymeric support mainly influenced the metal ion capacities and rates of equilibration. A remarkably high preference for cadmium ions was shown by a reagent containing a quinaldic acid with a phenacyloxy group in the 8-position of the quinoline ring. This reagent proved useful for the removal of cadmium from 30% phosphoric acid. © 1990.