| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 67431 | Journal of Molecular Catalysis A: Chemical | 2008 | 8 Pages |
Molybdovanadophosphoric acid (MVPA) supported zirconia was synthesized by an incipient wetness impregnation method taking zirconium hydroxide and MVPA as the precursors. The neat and supported catalysts were calcined at 500 °C and characterized by nitrogen adsorption–desorption, X-ray powder diffraction, FTIR, UV–vis DRS, temperature programmed reduction (TPR) and Raman spectroscopy techniques. The 15 wt.% MVPA stabilizes the tetragonal phase of zirconia, which leads to an increase in surface area. The Keggin structure of MVPA remains unaltered up to 500 °C. The catalytic activities were evaluated for hydroxylation of phenol using H2O2 as the oxidant. Among all the promoted catalysts, 15 wt.% molybdovanadophosphoric acid supported zirconia exhibits highest catalytic activity in phenol hydroxylation, giving 49% conversion having 61% para selectivity.
Graphical abstractMolybdovanadophosphoric acids supported zirconia (ZMVPA) is an efficient catalyst for phenol oxidation to hydroquinone and catechol. H2O2 reacts with ZMVPA to give hydroxyl radical through a redox mechanism, which attacks phenol ring to give hydroquinone and catechol as major products.Figure optionsDownload full-size imageDownload as PowerPoint slide
