The gas phase hydroxylation of aromatics is studied over Cu-modified phosphate catalysts. Benzene is converted to phenol in the presence of oxygen and ammonia at 450 degreesC. The same catalysts are active for benzene hydroxylation using nitrous oxide as the oxidant. Catalysts with different copper loading are tested and the effect of the structure of copper species on the yield of phenol is compared. The effect of used oxidants, water as well as possible reaction mechanism is discussed. (C) 2004 Published by Elsevier B.V.