ZSM-5 molecular sieve and preparation method thereof

Abstract

The invention relates to a ZSM-5 molecular sieve and a preparation method thereof. The preparation method comprises the following steps: according to the amounts of SiO2 of a silicon source, Al2O3 of an aluminum source, the TPA<+> of a template agent and the K<+> of a potassium source, uniformly mixing the silicon source, the aluminum source, the template agent, the potassium source and water in a mole ratio of 1: (0-0.075):(0.02-1):(0-5):(5-100), crystallizing for 8-180 hours at 120-200 DEG C, washing a solid product which is obtained through crystallization till the filtrate is neutral, drying and calcining, thereby obtaining the ZSM-5 molecular sieve, wherein the template agent is tetrapropylammonium hydroxide. According to the method, K<+> is adopted to effectively introduce the aluminum source into a zeolite molecular sieve, the crystal particle size of the prepared product is 500nm to 50mu m, the particle size is controllable and uniform, the silicon-aluminum ratio can be adjusted from 27 to pure silicon, the crystallization degree of the product is high, and the material can be widely used in multiple fields such as petrochemical engineering, adsorption separation and catalytic synthesis.

Description

technical field [0001] The invention relates to a ZSM-5 molecular sieve with a grain size between 500nm and 50μm, a silicon-aluminum ratio ranging from 27 to pure silicon, and a crystallinity of over 100% and a preparation method thereof. Background technique [0002] ZSM-5 molecular sieve was first invented in 1972 by Mobil Petroleum Company of the United States (US3702886). The molecular sieve has a three-dimensional intersecting channel system, and its pore window is a 10-membered ring. It belongs to a mesoporous zeolite. The entrance and exit channels provide a basis for the preparation of industrial catalysts with high selectivity, high activity, and strong anti-coking deactivation performance. At present, ZSM-5 and modified ZSM-5 are widely used in petrochemical fields such as shape-selective cracking, alkylation, isomerization, disproportionation dewaxing, and etherification of hydrocarbons. The high-silicon or even pure-silicon ZSM-5 molecular sieve has strong hydr...

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Problems solved by technology

[0009] The ZSM-5 molecular sieves synthesized in the above documents generally have relatively small grains, and often need to add seeds, or add other auxiliary components such as surfactants, organic additives, etc. during the synthesis process, making the synthesis process more complicated

In addition, the silicon-aluminum ratio of the molecular sieve synthesized by the above synthesis method is narrow, and with the decrease of the silicon-aluminum ratio, the crystallinity decreases significantly.

At the same time, the ZSM-5 grain size uniformity in the same sample prepared by it is not very high, which is unfavorable for exploring the influence of grain size on catalytic performance.

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