Synthesis of 2-Substituted Benzimidazoles in the Presence of Polyaniline Nanoparticles Doped With 12-Tungstophosphoric Acid as Reusable Heterogeneous Catalyst

Abstract

Polyaniline nanoparticles doped with 12-tungstophosphoric acid was prepared with different loading amounts of 12-tungstophosphoric acid. Doped polyaniline was characterized by XRD, SEM, and FT-IR techniques and the Keggin anion of heteropoly acid was detected on the polymer. Doped polymer was used as heterogeneous solid acid catalyst for the synthesis of 2-substituted benzimidazoles by the reaction of o-phenylenediamine with various types of aldehydes. The activity and reusability of the catalyst were found to be good.

Keywords:

• 12-tungstophosphoric acid
• benzimidazole
• doped polymer
• nanoparticles
• o-phenylenediamine
• polyaniline

Acknowledgments

The authors are thankful to the Yazd University Research Council for partial support of this work.