Preparation and properties of a neophyl type anion exchange resin

Abstract The common strongly basic Type I anion exchange resins, magnified image contain benzylictrimethylammonium groups. In OH− form, the resins are unstable above 60°C. due to nucleophilic attack by OH− on the benzylic and methyl carbon atoms. Reactivity of benzylic carbon sites relative to methyl sites is about 4 to 1. More stable resins would be desirable, so laboratory synthesis and stability study was made of a resin which contained neither benzylic carbon atoms nor β‐carbon atoms having hydrogen atoms which could give elimination reactions. This resin, magnified image containing neophyltrimethylammonium groups, nevertheless lost strong base capacity more readily than a comparative resin containing benzylic trimethylammonium groups. The breakdown was primarily at the methyl carbon atoms, however, so almost all weak base capacity was retained. The greater reactivity of methyl groups on the neophyl resin—relative to methyl groups on benzylic resin—can be due to internal compressional strain between the methyl groups of the nitrogen and the methyl groups of the β‐carbons.