MCM-22 zeolite molecular sieve containing rare earth heteroatoms in skeleton and preparation method thereof

Abstract

The invention relates to an MCM-22 zeolite molecular sieve containing rare earth heteroatoms in a skeleton and a hydrothermal synthesis method thereof. The method is characterized by comprising the following steps: regulating the pH value of the mixed solution of a silicon source and a rear earth source to perform co-hydrolysis and obtain a silicone gel precursor containing rear earth; then adding an organic template agent to obtain a solution A; mixing water, an aluminum source and an alkali source uniformly according to a certain proportion to obtain a solution B; slowly adding the solution B in the solution A dropwise to obtain a crystallization liquid; and placing the crystallization liquid in a hydrothermal kettle, sealing and performing the static hydrothermal crystallation for 5-30 days at 140-180 DEG C to obtain the skeleton rare-earth heteroatom molecular sieve MCM-22 with the MCM-22 crystal structure. The method avoids the phenomenon that only rare-earth heteroatoms are hydrolyzed to generate oxide precipitate; the crystallization process uses the static method without the stirring step, thereby simplifying the operating condition and reducing the production difficulty. In addition, the product has high crystallization degree and high hydrothermal stability and the preparation method has good repeatability.

Description

Technical field [0001] The invention relates to a MCM-22 heteroatom molecular sieve containing rare earth in the framework and a preparation method thereof. More specifically, the zeolite molecular sieve provided by the present invention has the characteristics of the crystal structure of MCM-22, and the zeolite molecular sieve crystal structure contains rare earth elements. Background technique [0002] MCM-22 zeolite molecular sieve is a zeolite molecular sieve material with MWW topology (US4954325) developed for the first time by Mobil Corporation of the United States. It has two independent and unconnected pore systems (Science, 1994, 264: 1910- 1912): First, the aperture is 4.0×5.9 The ten-membered ring two-dimensional sinusoidal channel; the second is through 4.0×5.4 The diameter of the opening of the ten-membered ring with the outside world is 7.1×7.1×18.2 The twelve-membered ring super cage. With its unique pore structure, good thermal / hydrothermal stability and suita...

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Problems solved by technology

Although the MCM-22 zeolite molecular sieve has shown important industrial application value, there are currently no patents and literature reports on the MCM-22 structure zeolite molecular sieve with a framework containing rare earth elements

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