Catalytic oxidative transformation of benzyl alcohol and cyclohexanol over mesoporous Mn-MCM-41,Mo-MCM-41 and Mo(Im),Mn-MCM-41 molecular sieves

摘要

Mesoporous Mn-MCM-41 and Mo-MCM-41 molecular sieves were synthesized by hydrothermal method using manganese chloride,ammonium molybdate and sodium metasilicate as the source for Mn,Mo and Si.Mo(Im),Mn-MCM-41 was synthesized by impregnating Mn-MCM-41 with ammonium molybdate by wet chemical method.These materials were characterized by XRD,TGA,FT-IR and ESR techniques.The vapour phase oxidation of benzyl alcohol and cyclohexanol was attempted over these molecular sieves as a probe reaction.The principal products were benzaldehyde and cyclohexanone.The activity of Mn-MCM-41 was found to be better than the other two catalysts.The influence of time on stream was studied at 300 deg C for both the reactions over Mn-MCM-41 and Mo-MCM-41 molecular sieves.The conversion decreased very slightly with increase in time on stream.