Hydroxylation of benzene with nitrous oxide on H-Ga-ZSM5 zeolite

A H-Ga-ZSM5 zeolite catalyst was applied for gas phase hydroxylation of benzene to phenol with nitrous oxide as oxidant. In a wide range of temperatures and partial pressures phenol was the main product. Up to reactor temperatures of 400 degrees C benzoquinone was the main by-product. Above 400 degrees C total oxidation of benzene started. Increasing partial pressures of benzene and particularly of nitrous oxide led to an increase of the reaction rate. Selectivity to the main product phenol was strongly affected by the benzene feed concentration. Rising benzene partial pressure led to increasing selectivity to phenol.