Direct oxidation of benzene to phenol catalyzed by a vanadium-substituted heteropolymolybdic acid catalyst

The direct synthesis of phenol by hydroxylation of benzene with hydrogen peroxide over a vanadium substituted heteropolymolybdic acid catalyst was investi- gated at 70 ºC. Hydrogen peroxide was used as the oxidant while 36 wt.% acetic acid was employed as the solvent. After 100 minutes, the selectivity for phenol was 93 % and the yield of phenol was 10.1 %. The catalyst was characterized by elemental analysis, thermogravimetry, infrared spectroscopy, UV-Vis spectroscopy, X-ray dif- fraction, and 31 P-NMR and 51 V-NMR techniques. The experimental conditions, such as reaction temperature, the amount of hydrogen peroxide and catalyst, were investigated. The as-prepared phenol could be separated by column chromatogra- phy and was characterized by infrared and mass spectrometry.