Efficient and Eco-Friendly Tungstate Promoted Zirconia (WO x /ZrO₂) Solid Acid Catalyst for the Synthesis of 2-Aryl Benzimidazoles

An eco-friendly catalytic amount (0.3 g) of tungstate-promoted zirconia (WO x /ZrO₂) solid acid catalyst has been explored in the synthesis of 2-aryl benzimidazoles using aryl aldehydes and o-phenylenediamine. This is one of the fundamental aspects in green chemistry for simple experimental and product isolation protocol combined with easy recovery and reusability of the catalyst. It is expected to contribute in the development of clean and environment friendly strategy for synthetic protocols. The incorporated promoter showed strong influence on the surface and bulk properties of zirconia. The catalytic activity results suggest that the methodology adopted offers significant improvements for the synthesis of benzimidazole derivatives with respect to yields, simplicity and green aspects by avoiding toxic conventional catalysts and solvents. Henceforth, a good substrate conversion and excellent product selectivity were obtained over tungstate promoted zirconia solid acid catalyst. Graphical Abstract A straightforward and general method has been developed for the synthesis of 2-aryl benzimidazoles using aryl aldehydes and o-phenylene diamine in the presence of eco-friendly tungstate-promoted zirconia (WO x /ZrO₂) solid acid catalyst.