Preparation method of MCM-22 molecular sieve

Abstract

The invention discloses a preparation method of an MCM-22 molecular sieve, which adopts a vapor-phase transfer method. The method comprises the following steps: mixing MCM-22 molecular sieve powder and water to form a suspension, and carrying out ultrasonic dispersion treatment to peel out the small-grain MCM-22 molecular sieve; and by using the small-grain MCM-22 molecular sieve as the crystal seed, mixing with silicon source, aluminum source, alkali and water to prepare a silicon-aluminum xerogel. Due to the existence of abundant small-grain MCM-22 molecular sieve in the silicon-aluminum xerogel, the small-grain molecular sieve has the function of crystal seed in the MCM-22 molecular sieve preparation process by the vapor-phase transfer method, thereby obviously shortening the crystallization reaction time of the molecular sieve, enhancing the molecular sieve preparation efficiency, and widening the silicon-aluminum range of the MCM-22 molecular sieve synthesized by the vapor-phase transfer method to some extent under the induction crystallization of the crystal seed. The method has the advantage of simple preparation process, and is easy to implement.

Description

technical field [0001] The invention relates to a preparation method of MCM-22 molecular sieve, which belongs to the technical field of molecular sieve synthesis. Background technique [0002] MCM-22 molecular sieve is a kind of microporous crystalline molecular sieve, which has two sets of independent pore systems of ten-membered ring and twelve-membered ring. The dual channel system of MCM-22 molecular sieve makes it exhibit both the channel characteristics of ten-membered rings and the channel characteristics of twelve-membered rings in some catalytic reactions. At the same time, MCM-22 molecular sieve also has high thermal stability, hydrothermal stability and suitable acidity. Therefore, MCM-22 molecular sieves show high application value in alkylation, aromatization and toluene disproportionation. [0003] At present, most of the research on the synthesis of MCM-22 molecular sieves is the imitation or improvement of the earlier published patent USP 4954325 of Mobile ...

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Problems solved by technology

[0006] It can be seen from the above documents that although compared with the conventional hydrothermal method, the single-pot yield of MCM-22 molecular sieve prepared by the gas phase transfer method is higher and the environmental pollution is less, but there is still a relatively long crystallization time and the resulting product silicon aluminum Disadvantages of being narrower than

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