The liquid-phase selective oxidation of a methylene group attached to an aromatic ring by molecular oxygen to a carbonyl group, using MnO4-1 -exchanged Mg-Al hydrotalcite (Mg/Al = 2-10) has been investigated in the absence of solvent. The methylene-to-carbonyl group oxidation activity of the MnO4-1 -exchanged hydrotalcite, as well as the H2O2 decomposition activity and basicity of Mg-Al hydrotalcite increased with increasing Mg/Al ratio of the catalyst. The MnO4-1 -exchanged Mg-Al-hydrotalcite is a highly active and selective, stable, and reusable catalyst for the oxidation of ethylbenzene to acetophenone and diphenylmethane to benzophenone by molecular oxygen in the absence of solvent. The reaction catalyzed by this environmental-friendly catalyst is truly heterogeneous, without leaching of the active component(s) from the catalyst. The catalyst showed better performance after its first use in the oxidation of both ethylbenzene and diphenylmethane. (C) 2004 Elsevier Inc. All rights reserved.