Synthesis Of Sn-MCM-41Nanoparticlesand Their Application In Catalysis

The successful discovery and synthesis of ordered mesoporous molecularsieve,M41S (MCM-41, MCM-48, MCM-50) series silicon oxide,extended the porediameter of molecular sieve from micropore to the field of mesoporous. Themesoporous materials MCM-41mixed with other metal atoms were the key point ofresearch because of whose the catalytic activity better then pure silicon. Due to thepresence of metal ions on the skeleton or metal elements loaded outside of the surface,MCM-41was given acid centers and redox sites, which owed structural features andproperties of porous in the mesoporous materials, at the same time, it owed thecatalytic properties of the metal ions.In this paper, ordered Sn-MCM-41nanoparticles synthesised by in-suit methodand post-synthesis method were successfully prepared under room-temperature usingdifferent tin and base contents, in which NaOH and CTAB were used as base sourceand surfactant. The samples were characterized by TEM, XRD, SEM, N2adsorption-desorption isotherms measurement, FT-IR and UV-vis spectroscopy.Besides, effects of the content of NaOH and tin source on the mesoporous structureswere investigated. Additionally, ordered Sn-MCM-41nanoparticles were obtained bythe post-synthesis method. Both in room-temperature and post-synthesis method,experiments and characterization results show the mesoporous Sn-MCM-41nanoparticles have good degree of order when the source of base amount is3.5ml;however when the addition amount of the sodium hydroxide solution is7ml, thedegree of order decreased obviously.The samples prepared by the two synthetic methods were used as catalysts inadamantanone Baeyer-Villiger hydroxylation with H2O2as oxidant. Experimentsresults show that Sn-MCM-41nanoparticles showed higher catalytic activity in theadamantane Baeyer-Villiger catalytic oxidation reaction. In the reaction system, therate of adamantane conversion enhances unceasingly. After a certain time, the rate ofadamantane conversion is no longer change. In the end of the reaction, the adamantanereaction rate up to98%. Sn-MCM-41nanoparticles reusing activity did not reduceafter four times in room temperature synthesis method.