Benzene and mesitylene (1,3,5-trimethylbenzene) are oxidized to phenol and to the corresponding aldehyde (3,5-dimethylbenzaldehyde), respectively. in CH3CN at room temperature, by aqueous hydrogen peroxide, in acidic medium, in reactions catalyzed by vanadium(IV or V) compounds with N,O-ligands (such as Amavadine models and related ones), namely of the types triethanolamine and (hydroxy-imino)dicarboxylic acid (basic forms) or comparable ligands. The effects of the ligands, of the relative amounts of reagents and of the temperature are also reported. (C) 2004 Elsevier B.V. All rights reserved.