The Synthesis And Application Of Mesoporous Sieves MCM-48

The mesoporous sieve of the M41S family has framewoks with pore diameters withinthe mesoporous range(2～10nm), huge surfaces areas about 1000cm2/g and amorphism porouswall tent to incorporate hetero atom so that has been used abroad in big moleculer catalysisand separation, life science and environment protection fields and so on. Especially theMCM-48 has two disconnected porous networks, which is three dimensional pore system.Moreover, it could strengthen the process of materials transfer in the reaction, retard the cokeaccumulation on catalyst, and has sharp selective catalysis to some big moleculer reaction, sothis thesis choose MCM-48 as the target to synthesize, research the prepare condition of theSi-MCM-48 and its supported film and the effect of the dosage of template, the silicatesources, the alkali sources, crystal time and crystal temperature to the phase structure ofproduct. Based on those conclusions, different aluminum sources and titanium sources areintroduced to the pure silica system under the optimization prepare conditions to preparehetero atom sieves Al-MCM-48 and Ti-MCM-48 and its phase structure, surface morphologyand the exist and distribution of titanium atom in framework are characterized by XRD, SEMand UV-vis analysis.In the process of prepare hetero atom sieves Al-MCM-48 and Ti-MCM-48, the effectof the alkalinity of the synthesis to the phase structure of the final product is discussed chiefly.After the addition of the hetero atom sources, the hexagonal (MCM-41), cubic (MCM-48) andlamellar (MCM-50) symmetry could be synthesized in order while the alkalinityin increaseingin sodium aluminate system by adjusting the alkalinity of the reaction mixture exactly, butfollow the opposite order while the alkalinityin increaseing in aluminum sulfate andaluminum isopropoxide system. So the Al-MCM-48 with high content of aluminum atom(Si/Al=20) could be gained by control the alkalinity. Then, the similar phase transition rule isdetected when synthesize the Ti-MCM-48 using titanium tetrachloride as the titanium sourcesand the cubic mesoporous sieve with high centent of titanium atom (Si/Ti=50) could also begained if the system has not excess isopropanol which will weaken the effect of the alkalinity.In the end, the catalysis of Al-MCM-48 in alkylation of benzene, transalkylation andcracking of Diisopropylbenzene and Ti-MCM-48 in oxidation of styrene is researched.