A Study On Synthesis And Catalysis Of Hierarchical Nanosheet Zeolites

The mainly contents of this dissertation focus on the hierarchical zeolite, which conclude the synthesis process, the characterization of the material and the catalysis of different kind of hierarchical zeolites. A novel synthesis method of the hierarchical zeolite is further characterized by some new instruments. And the MWW-type layered hierarchical zeolites are synthesized using the method above. The catalytic behaviors of these hierarchical zeolites are also investigated. Besides, the new germanosilicate hierarchical zeolites are synthesized in a new way.We present a strategy that designing a zeolite seed and CTAB-assisted dissolution-recrystallization route to direct synthesis of highly ordered swelling-type multilamellar zeolite Al-ECNU-7P and Ti-ECNU-7P, both of which consist of alternatively stacking sequence of inorganic MWW nanosheets and organic CTAB layers. Based on the former research of our group,2D 1H-29Si solid-state NMR, X-ray, electron microscopy and rotation electron diffraction (RED) analyses provide molecular-level insights into the mechanism of self-assembly and the interaction between simple surfactant CTAB and inorganic layers. Moreover, the calcined form Al-ECNU-7 possesses a high delamination degree due to partial condensation and proves to serve as a highly active, selective and stable solid acid catalyst for bulky molecules conversion. Another similar hierarchical material, Ti-ECNU-7, was also successfully synthesized and used as catalysts in the liquid-phase selective oxidations. The catalyst exhibited a superior catalytic performance in the epoxidation of bulky olefins, probably due to the hierarchically porous structure and the highly exposure of active centers.The germanosilicate hierarchical nanosheet zeolite ECNU-11 is synthesized under the direction of the imidazolium hydroxide as the OSDA with the assisting of the halide ions. The imidazolium hydroxide which is the ionic liquid terns into the micellar with adding the inorganic salts and the micellar will direct the crystallization.