An octahedral molecular sieve composed of Mn, Mg and 0 is known as todorokite. Here, synthesis of todorokite containing Al in its framework was studied and its formation by the hydrothermal method was, for the first time, confirmed by combining the results of ICP, XRD and TEM. There existed a limitation to the amount of Al that could be incorporated into the structure, probably because of the cation-to-cation repulsion in the channel. The oxidation of cyclohexane with tert-butyl hydroperoxide was studied as a model reaction. Results revealed that Al-containing todorokite and proton-exchanged Al-containing todorokite promoted the reaction to cyclohexyl alcohol and cyclohexanone. (c) 2005 Elsevier B.V. All rights reserved.