Self-assembled Mg5(CO3)4(OH)2 • 4H2O nanosheet as an effective catalyst in the Baeyer-Villiger oxidation of cyclohexanone

Novel self-assembled Mg(5)(CO(3))(4)(OH)(2) center dot 4H(2)O with nanosheet structure was fabricated through simple hydrothermal method without any templates. Series of MgCO(3) and MgO catalysts with nanosheet structures were also prepared by calcining Mg(5)(CO(3))(4)(OH)(2) center dot 4H(2)O at different temperature. The samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), N(2) adsorption-desorption, Fourier transform infrared (FTIR) and differential thermal analysis-thermogravimetry (DTA-TG). It was found that all the Mg-based catalysts exhibited regular nanosheet structure with high surface area. Although all of them are efficient catalysts for the Baeyer-Villiger oxidation of cyclohexanone to the corresponding lactone with aqueous hydrogen peroxide as the green oxidant, the Mg(5)(CO(3))(4)(OH)(2) center dot 4H(2)O surpassed all of them and the catalytic activity (mmol g(cat)(-1)) are higher than those Mg-based catalysts reported by other groups. The higher surface area, the special nanosheet structure as well as the enriched OH(-) and CO(3)(2-) species on the Mg(5)(CO(3))(4)(OH)(2) center dot 4H(2)O catalysts all account for its higher activity. (C) 2007 Elsevier B.V. All rights reserved.