| Hierarchical molecular sieve and nanosized mesoporous molecular sieve, which are suitable for the conversion of large molecules, are hot topics in material and catalysis. The purpose of this thesis is to synthesize novel hierarchical mesoporous molecular sieve ZK-1(ZSM-5/KIT-1) and nanosized molecular sieve A1KIT-1by simple method. The framework structure, porosity, morphology and acidic properties of the obtained materials were characterized by X-ray diffraction, infrared spectroscopy, UV-Raman spectroscopy, N2adsorption isotherm, electron microscopy and NH3-temperature programmed desorption et al. The catalytic properties were evaluated by the probe reactions. The main results are as follows:The Nano-ZSM-5zeolite was synthesized by hydrothermal crystallization of clear supersaturated homogeneous synthesis mixtures. Effects of different aluminum sources, template agent proportion and amount of water were studied. The Nano-ZSM-5zeolite with particle size of50-150nm can be synthesized using aluminum isopropoxide and sodium aluminate as the aluminum sources. Crystallization is completed in1h and the stable crystallization period is1-72h.The nanosized A1KIT-1mesoporous molecular sieve has been hydrothermally synthesized in the absence of organic s’alts. The A1KIT-1has a particle size of60-100nm, and a three-dimensional network structure with the pore sizes of2.7nm and～50nm. The method is simple and easy to control compared with the other reported methods. The present method does not need to add the organic salt, and repeatedly adjust the pH value. The nanosized AIKIT-1retains74%of the surface area and83%of the pore volume after the steaming treatment, indicating its good steam stability. The Nano-A1KIT-1sample shows better catalytic performance in the conversion of1,2,4-trimethylbenzene than HMCM-41and HZSM-5.The micro-mesoporous ZK-1(ZSM-5/KIT-1) molecular sieves have been hydrothermally synthesized by using dual templates (TPAOH and CTAB) in only one step. The effect of synthesis conditions on the structure of the materials are investigated in detail. The structure of ZK-1is divided into two types:ZK-1(â… ) the KIT-1containing ZSM-5building units; ZK-1(â…¡), a mixture of ZSM-5and KIT-1. Crystallization temperature, crystallization time, amount of template are the key to controlling the structure. The lower crystallization temperature, shorter crystallization time and more amount of template are better for the formation of ZK-1(â… ). The structure of ZK-1is controlled by the crystallization temperature and time. Lower crystallization temperature (90-130℃) favors the formation of the ZK-1(â… ), while the higher crystallization temperature (140-170℃) promotes the formation of ZK-1(II). At170℃, with increasing the crystallization time, the ZK-1experienced phase transformations in the sequence ZK-1(â… )->ZK-1(â…¡)â†'ZSM-5.The ZK-1exhibits good hydrothermal stability. The micro-mesoporous structures are maintained after the treatment in boiling water for120h or in steam at700℃for2h. The ZK-1shows better catalytic performances in the conversion of o-ethyltoluene than AIKIT-1. The sulfided CoO-MoO3/ZK-1shows good catalytic performance in the selective hydrodesulfurization of full-range FCC gaseline and4,6-DMDBT... |
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