Study on the synthesis of heteropoly acids and their catalytic performance for the direct hydroxylation of benzene to phenol

The molybdovanadosilicic and tungstovanadosilicic acids have been prepared by multi-step method.ICP,TGA,IR and XRD characterizations revealed that the compounds synthesized in the present work have Keggin structure.The catalytic performance of the heteropoly acids obtained for the direct hydroxylation of benzene to phenol is also investigated.17.2%phenol yield with more than 90% selectivity has been obtained.