Sulfonic-acid-functionalized activated carbon made from tea leaves as green catalyst for synthesis of 2-substituted benzimidazole and benzothiazole
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A simple and efficient procedure for synthesis of 2-substituted benzimidazole and benzothiazole has been developed by using sulfonic-acid-functionalized activated carbon as heterogeneous catalyst. The activated material was prepared from matured tea leaf in presence of phosphoric acid as activating agent. The final catalyst was prepared by anchoring –SO3H group on the surface of the activated carbon. The catalyst could be easily recovered and reused for more than three catalytic cycles without significant loss in catalytic activity. The catalytic performance of the catalyst was found to be superior to that of a similar catalyst prepared from montmorillonite K10.
KeywordsActivated carbon Sulfonic acid Heterogeneous catalysis Benzimidazole Benzothiazole
Financial support from DST [grant no. SR/NM/NS-18/2011(G)] is gratefully acknowledged. M.M.D. thanks UGC for a research fellowship. We also acknowledge support from the Department of Chemistry, Gauhati University, SAIF-GU, SAIF-NEHU, and CIF-IITG for all the analytical facilities used during the course of this investigation.