Polyamine ion-exchange resins from polyepichlorohydrin: Resins with improved resistance to oxidation

Abstract

The preparation of polyamine ion-exchange resins from crosslinked polyepichlorohydrin is described. The crosslinking agents used were hydroquinone, 1,3-propanedithiol, 1,3-dimercaptobenzene, piperazine, N,N′-dimethyl-1,6-hexanediamine, 1,6-diaminohexane and bis(3-aminopropyl)amine. The pendant chloromethyl groups were reacted with either pyrrolidine, piperidine, homopiperidine, di-n-propylamine, dimethylamine, diethylamine or bis(3-aminopropyl)amine. The effects of the amount and the nature of the crosslinking agent, the solvent, the aminating amine and other factors on the resin properties are reported. The resin properties of interest are those which are important when the resin is used in a thermally regenerable system. These resins have capacities and base strengths which are similar to those of the polyalkyldiallylamine-type resins and they are ten times more resistant to oxidation by oxygen than the polyalkyldiallylamine resins. The titration curves for the former resins slope more than those of the latter. The polar polyether backbone of the polyepichlorohydrin has a dominating effect on the slope of the titration curves of the polyamine resins. An effect of hydrophobic groups on the slope of titration curves and the ease of oxidation of the resin was found.