不同金属氧化物在SBA-15表面分散度对其性能的影响

Influence of dispersion of different metal oxides within the channels of SBA-15 on its physico-chemical properties

通过湿浸渍法,制备了一系列介孔KF/M-SBA-15(M=Mg, Al, Zn, Zr, La, Ce)固体碱催化剂。采用XRD,TG,N_2吸附-脱附和TEM等手段对催化剂结构与性能进行了表征。结果表明:所制备的KF/M-SBA-15的介孔有序性与所引入的金属氧化物在其表面的分散程度有关。MO_x(M=Mg, Al, Zn或La)在SBA-15表面分散度较高,能够形成"致密"的保护层,且所合成的KF/M-SBA-15具有有序介孔结构和强碱性能。在催化环氧丙烷与甲醇的开环反应中,KF/M-SBA-15显示了优异的催化活性:丙二醇甲醚的收率与1-甲氧基-2-丙醇的选择性均达到了90%以上。

By a modified wetness impregnation method,a series of KF/M-SBA-15(M=Mg,Al,Zn,Zr,La or Ce)solid bases was successfully prepared.The obtained materials were characterized by XRD,TG-DTG,N 2 adsorption-desorption,TEM and acid-base titration measurements.The results demonstrate that the dispersion degree of the single metal oxides on the surface of SBA-15 strongly depends on the ordering of mesoporous KF/M-SBA-15.The MO x(M=Mg,Al,Zn or La)can be highly dispersed on the surface of SBA-15 to form an intact interlayer.The resultant KF/M-SBA-15 materials possess both mesoporous structure and strong basicity.In the ring-opening reaction of propylene oxide with methanol,the KF/M-SBA-15 exhibits excellent catalytic performance with yield of propylene glycol methyl ether and the selectivity to 1-methoxy-2-propanol both reaching more than 90%.