Selective nitration of phenol over sulfated titania systems prepared via sol–gel route

Titania, sulfated titania and a series of iron loaded sulfated titania catalyst with different iron loadings (3% to 9%) are prepared by sol–gel method and calcined at 500 °C. Anatase is found to be the active phase with crystallite size in the nano range. All the prepared catalysts are found to be stable up to 700 °C. Phenol is nitrated regioselectively to ortho-nitrophenol by concentrated nitric acid over these catalysts. Catalytic activity well correlates with the Brönsted acid sites of these catalysts.