| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 50783 | Catalysis Communications | 2012 | 5 Pages |
A novel silica tungstic acid (STA) as a highly efficient catalyst has been synthesized and employed for the cyclocondensation of 1,2-phenylenediamines with orthoesters under solvent-free conditions. Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding benzimidazoles at 80 °C. To make the catalyst, sodium tungstate reacted with silica chloride under refluxing n-hexane. The STA as a novel solid acid was characterized by X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New silica tungstic acid (STA) was prepared through the simple experimental procedure. ► Silica tungstic acid was characterizaed by XRD, XRF and FT-IR spectroscopy. ► Silica tungstic acid was used as a green solid acid catalyst. ► Silica tungstic acid is recyclable and also exhibited very high activity.
