Synthesis of FE-MCM-41 Nanoparticles and Their Application in Catalysis
|School||Harbin Institute of Technology|
|Keywords||Fe-MCM-41 nanoparticles room-temperature method post-synthesis method phenol hydroxylation Friedel-Crafts|
Pure silica MCM-41 with weak acidity has no catalytic activity in selective oxidation reaction. Iron-substituted MCM-41 has better catalytic activities via incorporation of iron in the mesoporous framework. Furthermore, particle size plays an important role in the catalytic properties, that is, mesoporous nanoparticles display improved catalytic performance in some catalytic reactions compared with corresponding large particles.In this paper, ordered Fe-MCM-41 nanoparticles with various iron contents were successfully prepared via room-temperature method, in which NaOH and CTAB were used as alkaline source and surfactant, respectively. The samples were characterized by SEM, TEM, XRD, N2 adsorption-desorption isotherms measurement, FT-IR and UV-vis spectroscopy. Besides, effects of the content of NaOH, CTAB and iron source on the mesoporous structures were investigated. Additionally, ordered Fe-MCM-41 nanoparticles were obtained by the post-synthesis method.The samples prepared by the two synthetic methods were used to be catalysts in phenol hydroxylation with H2O2 as oxidant. It was found that Fe-MCM-41 nanoparticles indicated higher initial reaction rate and effective utilization of hydrogen peroxide, achieving the given phenol conversion at a shorter reaction time. This is mainly because mesoporous nanoparticles can facilitate the diffusion of reactant molecules in the shorter mesoporous channels. In addition, Fe-MCM-41 nanoparticles can be catalyst for Friedel-Crafts reaction with benzyl chloride and benzene, in which benzyl chloride conversion could be up to 100% in a short time.