Nitration of phenol over silica supported H4PW11VO40 catalyst
Vanadium incorporated tungstophosphoric acid (TPAV1) supported on silica was synthesized and characterized by BET-surface area, Fourier transform infrared spectroscopy, X-ray diffraction and Laser Raman techniques. Nitration of phenol was studied at room temperature (25 °C) using HNO3 in the presence of 0–20 wt.% TPAV1/SiO2 catalysts taking 1, 2-dichloroethane as solvent. The effects of various parameters such as phenol/HNO3 mole ratio, reaction time, catalyst weight, and stirring speed on the catalyst activity were studied. 8 wt.% TPAV1/SiO2 has shown the best activity, regioselectivity and reusability in the nitration of phenol, with a conversion of 92.6% and o-nitrophenol selectivity of 97.9%.
Graphical abstractSelective nitration of phenol to corresponding ortho-nitro phenol using mild HNO3 was studied at RT (25 °C) over heterogeneous silica supported vanadium incorporated tungstophosphoric acid catalyst and high yields were obtained.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Regioselective nitration of phenol to ortho nitrophenol. ► Phenol nitration was carried out at low temperature (25 °C). ► High product yield within reasonable time for 3 h.
Journal: Catalysis Communications - Volume 18, 10 February 2012, Pages 37–40