Synthesis method of high-silicon b-oriented ZSM-5 nanosheets

Abstract

The invention discloses a synthesis method of high-silicon b-oriented ZSM-5 nanosheets. The method is characterized by comprising the following steps: mixing an aluminum source with ammonia water, inorganic salts and water, stirring, slowly and dropwisely adding a silicon source, adding a template and a crystal seed at a uniform speed, and carrying out crystallization reaction at 120-190 DEG C for 24-48 hours; and after the reaction finishes, filtering, and drying to obtain the high-silicon b-oriented ZSM-5 nanosheets. Compared with the prior art, the ZSM-5 nanosheets have the advantages of high activity, ultrathin crystal grains, high silicon b-orientation, adjustable silica-alumina ratio, controllable thickness, perfect crystals and high hydrothermal stability, well overcome the defect that the preparation of the nanosheet zeolite catalyst requires the use of the specific-structure high-price structure guide agent or secondary template, have the characteristics of lower preparation cost and high synthesis yield, and have certain industrialized application prospects and obvious economic value.

Description

technical field [0001] The invention relates to the technical field of zeolite molecular sieve synthesis, in particular to a method for synthesizing high-silicon b-orientation ZSM-5 nanosheets. Background technique [0002] Mobil Corporation of the United States first reported the synthesis of ZSM-5 molecular sieve in 1972 (USP3702886). Due to the unique intersecting pore structure, high hydrothermal stability and shape selectivity, adjustable silicon-aluminum ratio, and strong acidity, MFI zeolite has gradually developed into the preferred catalytic material in the field of petrochemical industry. It is widely used in ether to propylene, alkylation reaction, methanol conversion to gasoline, toluene disproportionation and other devices. In recent years, the preparation of hierarchically porous ZSM-5 molecular sieves with nanosheet structure has become one of the hotspots in the field of catalytic materials research. In the prior art, Ryong Ryoo et al. (J. Am.Chem. Soc., 20...

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Problems solved by technology

Yingcai Long etc. (Micopor. Mesopor.Materials, 2006,95,234 and CN 1332114A), reported in the patent literature using dual-mode agent and the method of adding BETA seed crystals, can obtain the high-silicon MOR zeolite of b-axis orientation, but this This synthesis method needs to use two kinds of templates, the synthesis cost is expensive, and the obtained particles are also very thick strip-shaped MOR zeolite, and fluoride ions need to be added in the synthesis system, the synthesis process is complicated

[0005] The b-axis oriented high-silica zeolite prepared in the prior art requires the use of two templates, and the addition of fluoride ions to the synthesis system. The synthesis process is complex and expensive, and the obtained particles are also very thick long strip crystal grains.

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