Photocatalytic oxidation of benzene in a microreactor with immobilized TiO2 thin films deposited by sputtering

A microreactor with immobilized anatase TiO2 thin films, whose thickness and crystallinity were precisely controlled by sputtering technique, has been developed. Photocatalytic oxidation of benzene in the microreactor resulted in the direct production of hydroquinone with quite high yield by a four-hole reaction mechanism in contrast to a free phenol mechanism. The results indicate capabilities of microreactor with immobilized photocatalyst to be applied for organic synthesis involving multi-hole and/or multi-electron, which may provide new reaction selectivity not obtainable in the conventional batch reactors.