Chemistry of crown ethers. XVII. Triphase catalysis by immobilized benzo‐18‐crown‐6

Several immobilized benzo‐18‐crown‐6 derivatives have been synthesized and a study has been made of their activities as triphase catalysts in the reaction between 1‐bromooctane in toluene and aqueous potassium cyanide. In each case the reaction rate was proportional to the 1‐bromooctane concentration and to the amount of catalyst and also depended on the potassium cyanide concentration. Under non‐stirred conditions the activity per crown ether moiety was dependent on the degree of functionalization of the supporting polymer, being high for a highly substituted polystyrene/divinylbenzene resin and low for a sparingly substituted one. The beneficial effect of the high loading disappeared completely, however, under stirred conditions. The triphase catalyst can be used both with liquid‐liquid‐solid and with solid‐solid‐liquid systems and can be recovered without significant loss of activity.