Self-assembled Mg5(CO3)4(OH)2 · 4H2O nanosheet as an effective catalyst in the Baeyer–Villiger oxidation of cyclohexanone
Novel self-assembled Mg5(CO3)4(OH)2 · 4H2O with nanosheet structure was fabricated through simple hydrothermal method without any templates. Series of MgCO3 and MgO catalysts with nanosheet structures were also prepared by calcining Mg5(CO3)4(OH)2 · 4H2O at different temperature. The samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 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 Mg5(CO3)4(OH)2 · 4H2O surpassed all of them and the catalytic activity (mmolgcat-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 CO32- species on the Mg5(CO3)4(OH)2 · 4H2O catalysts all account for its higher activity.
Journal: Catalysis Communications - Volume 9, Issue 6, 31 March 2008, Pages 1334–1341