ZSM-35 molecular sieve preparation method

Abstract

The invention relates to a ZSM-35 molecular sieve and a preparation method thereof. The method comprises: carrying out mixing gelling on a silicon source, an aluminum source, an alkali, water, an organic template agent I and an organic template agent II, carrying out hydrothermal crystallization, filtering, washing, drying, and roasting to obtain a ZSM-35 molecular sieve, wherein the ZSM-35 molecular sieve has a sheet-like structure along the c-axis direction. According to the present invention, through the synergistic action of the organic template agent I and the organic template agent II, the prepared nano-sheet-like ZSM-35 molecular sieve has characteristics of small particle size and high specific surface area, wherein the diffusion rate is obviously improved through the small particle size, such that the reactant molecules and the product molecules can rapidly enter and exit the molecular sieve pore channels so as to reduce the occurrence probability of carbon deposition, the gapbetween the molecular sieves is large, and the thickness and the particle size are small so as to prolong the regeneration cycle of the catalyst and improve the selectivity of the product.

Description

technical field [0001] The invention belongs to the technical field of ZSM-35 molecular sieve preparation, and relates to a ZSM-35 molecular sieve and a preparation method thereof. Background technique [0002] ZSM-35 molecular sieve is a medium-porous zeolite developed by Mobil Corporation, with a FER-type framework structure. Naturally occurring FER zeolite is a silicon-rich crystalline zeolite whose crystal structure belongs to the orthorhombic system. It has a two-dimensional channel structure perpendicular to each other, that is, a ten-membered ring channel (0.42×0.54nm) parallel to the (001) plane and an eight-membered ring channel (0.35×0.48nm) parallel to the (010) plane. The ring channel and the six-membered ring channel intersect in the C direction to form a spherical cage (FER cage). [0003] The catalytic performance of molecular sieves is closely related to the crystal structure and morphology of molecular sieves. With its unique ten-membered ring structure, ...

AI Technical Summary

Problems solved by technology

However, the residence time of the ZSM-35 molecular sieve prepared by this method is too long, the diffusion performance of reactants and products in the molecular sieve is not good, and under the condition of too many acid sites, n-butene dimerization easily occurs to form octane Cracking of ene and octene into propylene and pentene, hydrogen transfer and coking and other side reactions

Once carbon deposits are formed in the catalytic reaction, the selectivity of isobutene and the stability of the catalyst cannot be guaranteed

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