Epoxidation Of Propylene By Cumene Hydroperoxide Over TI-MCM-41 And Mo-MOF Catalysts

Propylene oxide(PO)is mainly produced by two methods in the world: the chlorohydrin method and the Halcon method.These methods either produce plenty of pollution,or result much coproducts and costly.In the process with cumene hydroperoxide(CHP)as oxidant,the reaction conditions are mild and there are no byproducts.The traditional industial methods may be replaced by the CHP process.In this paper,mesoporous Ti-MCM-41 and Mo-containing MOF are used as catalysts in the propylene epoxidation by CHP.In order to increase the CHP efficiency and the PO selectivity,Ti-MCM-41 s were modified by different methods.Two types of Mo containing metal-organic frameworks,Mo@COMOC-4 and PMA@MIL-101(Cr),their catalytic performance was compared with MoO3/SiO2 as catalyst in the propylene epoxidation.Ti-MCM-41 samples were nitrided with NH3 in different conditions and characterized by CHN elemental analysis,XRD,N2 adsorption-desorption,FT-IR Py-IR and UV-Vis.After nitriding with NH3 at high temperature,all Ti-MCM-41 samples still retained the MCM-41 hexagonal structure.The N content of Ti-MCM-41 increased with nitridation temperature.In the propylene epoxidation reaction,the catalytic activity reduced for the nitided Ti-MCM-41 catalysts.But the catalysts acid strength decreased by introducing N species,thus restrained CHP decomposition and increased the CHP efficiency.Ti-MCM-41 catalyst nitrided with NH3 at 400 ? for 4 h without removing template,can increase the CHP efficiency to 79.6%.The characterization showed that the silylated Ti-MCM-41 samples modifid by trimethylchlorosilane(TMCS)are more hydrophobic.In the propylene epoxidation reaction,higher CHP efficiency and PO selectivity can be attained for the silylated Ti-MCM-41 catalysts.Mo containing Metal Organic Frameworks,Mo@COMOC-4 showed good catalytic activity in the epoxidation of propylene by CHP.After reusing for 5 runs,Mo@COMOC-4 maintained its crystallinity and catalytic activity.