liquid phase bromination of phenols over silicotungstic acid immobilized on nickel oxide nanoparticles

heteropoly acid promoted nanoparticle of nickel oxide samples were prepared by sol-gel method using heteropoly acids. prepared composite was characterized by xrd, ft-ir and icp technique. in this work, we have reported bromination of phenol, its derivatives and some aromatic compounds. the liquid phase bromination of phenol was performed using heteropoly acids immobilized nanoparticle of nickel oxide as catalyst, kbr as brominating agent and hydrogen peroxide as an oxidant in acetonitrile at room temperature. the reaction proceeds through the formation of br+ (bromonium ion), which attacks the phenol ring forming different brominated products. prepared catalyst can be used several times without a significant decline in catalytic activity.