Synthesis of Benzimidazoles Using Polystyrene-Supported Chloroaluminate Ionic Liquid as a Polymeric Lewis Acid Catalyst

Polystyrene-supported chloroaluminate ionic liquid was prepared from the reaction of Merrifield resin with 1-methylimidazole followed by reaction withaluminium chloride. This catalyst was used as a new chemoselective Lewis acid catalyst for the exclusive synthesis of 2-substituted benzimidazoles from thereaction of aldehydes with o-phenylenediamine. The catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency