MgO催化剂上以H2O2为氧源的苯乙烯环氧化反应

采用直接焙烧Mg(NO3)2·6H2O制备了固体MgO催化剂,并以H2O2为氧源,乙腈为溶剂,考察了其对苯乙烯环氧化反应的催化性能.运用X射线衍射、N2吸附-脱附、热重和CO2程序升温脱附对催化剂进行了表征.结果表明,MgO表面碱的强度在苯乙烯环氧化反应中起主导作用,而其表面的碱量、比表面积及孔体积等的影响较小.经75...

Epoxidation of Styrene with Hydrogen Peroxide over MgO Catalyst

A solid MgO catalyst was prepared by direct thermal decomposition of the Mg(NO3)2·6H2O precursor.The epoxidation of styrene was studied over the MgO using H2O2 as an oxidant in the presence of acetonitrile as solvent.The catalyst samples were characterized by X-ray diffraction,N2 adsorption-desorption,thermogravimetry,and CO2 temperature-programmed desorption.The results indicated that the strength of basic sites on the MgO catalyst is the key factor for the excellent performance of the catalyst.Enhancement of the strength of basic sites can increase the styrene conversion.In contrast,the number of basic sites,surface area,and pore volume of MgO have a relativelyminor effect on catalytic activity.The MgO sample prepared by calcining Mg(NO3)2·6H2O at 750 oC showed the most strength of basic sites and the highest catalytic activity among the MgO samples calcined at 450-850 oC.Under the optimized reaction conditions,H2O2/styrene molar ratio=6,acetonitrile as solvent,60 oC,and 10 h,the conversion of styrene and the selectivity to epoxyethylbenzene were 97.0% and 88.4%,respectively.