Preparation method of multistage porous material

Abstract

The invention provides a preparation method of a multistage porous material. The preparation method comprises following steps: step one, preparing a guiding agent; step two, preparing SBA-6 and ZSM-12composite molecular sieve slurry; step three, preparing Y/SBA-6 and ZSM-12 composite molecular sieve slurry; and step four, preparing a Y/SBA-6/ZSM-12/ASA multistage porous material. The prepared multistage porous material has the characteristics that the crystal grains of the NaY molecular sieve of the composite molecular sieve of the multistage porous material are small (100 to 400 nm), the silicon/aluminum ratio of the framework is high; the thermal stability is improved, compared with a corresponding NaY molecular sieve, the heat destroying temperature is increased by at least 5 DEG C, and a micro-meso pore structure, which is formed by micro pores with a diameter less than 1 nm and mesopores with a diameter of 3 to 10 nm, is formed.

Description

technical field [0001] The invention provides a method for preparing a hierarchically porous material, in particular to a method for preparing a Y / SBA-6 / ZSM-12 / ASA hierarchically porous material. Background technique [0002] Molecular sieve complex refers to a composite material that combines molecular sieves and other substances through the interaction between molecules, atoms or ions. Regular materials with mesoporous structures such as MCM-41 mesoporous molecular sieves are suitable for the transformation of organic macromolecules due to their large pore structure, but their poor thermal stability, hydrothermal stability and weak acidity limit their Applications of this type of material in the field of catalysis. The research on microporous-mesoporous composite materials based on high stability and strong acidic microporous molecular sieves has important industrial application value. [0003] With the continuous development of catalytic applications of molecular sieves...

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Problems solved by technology

The disadvantage of this method is that the preparation time is longer

[0013] The preparation methods of micro-mesoporous composite materials mentioned in the above documents or patents are either complicated in process or take a long time in the synthesis process

CN102000604A introduces a microwave treatment process in the process of synthesizing Y / MCM-41 composite molecular sieve, increases auxiliary equipment, and greatly increases the cost of synthesizing composite molecular sieve

In addition, the mesoporous part in the micro-mesoporous composite material mentioned in the above documents or patents is irregular pores

In the above patents, heteropolyacids are generally loaded or mixed with macroporous amorphous structure materials such as alumina and silica-alumina, but these materials have relatively low specific surface area compared with regular and ordered mesoporous materials, which reduces the specific surface area of ​​heteropolyacids. Catalytic activity

Due to the small pore size of microporous molecular sieves and relatively large heteropolyacid molecules, the loss of specific surface area and pore volume after loading is large, and it is difficult to exert catalytic activity.

The mesoporous molecular sieves developed in recent years have greatly improved the specific surface area, pore volume and pore size of molecular sieves. However, mesoporous molecular sieves such as SBA-15 and MCM-41 have poor thermal stability. Collapse, prone to permanent loss of catalytic activity

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