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Method for preparing mesoporous MCM-22 silicon aluminum molecular sieve

A technology of MCM-22 and silica-alumina molecular sieve, which is applied in the direction of crystalline aluminosilicate zeolite, etc., can solve the problems such as the difficulty of using supercage acid sites, achieve the improvement of internal diffusion limit, reduce the diffusion distance, and keep the crystallinity intact Effect

Inactive Publication Date: 2012-10-17
EAST CHINA NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limitation of the pore size of the ten-membered ring, the acidic sites in the supercage are difficult to be utilized.

Method used

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  • Method for preparing mesoporous MCM-22 silicon aluminum molecular sieve
  • Method for preparing mesoporous MCM-22 silicon aluminum molecular sieve
  • Method for preparing mesoporous MCM-22 silicon aluminum molecular sieve

Examples

Experimental program
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Effect test

Embodiment 1

[0020] Mix the reaction mixture of 1 g of MCM-22 molecular sieve synthesized by conventional hydrothermal method, 1.42 g of PI and 50 mL of 0.1M NaOH solution evenly, put it into a closed reaction autoclave, react at 170 ° C for 1 h under autogenous pressure, and cool with tap water. After filtering, washing, drying at 100°C overnight, calcining at 550°C for 6 hours, 4 Cl 3 After secondary ammonium exchange, it is calcined again at 550° C. for 6 hours to obtain the mesoporous molecular sieve of the present invention. Its BET specific surface area is 523 square meters per gram, and the outer specific surface is 242 square meters per gram. The X-ray diffraction spectrum of the product is shown in figure 1 ; The adsorption-desorption spectrum of nitrogen adsorption at low temperature is shown in figure 2 ; transmission electron microscope photos see image 3 .

Embodiment 2

[0022] Mix the reaction mixture of 1g of MCM-22 molecular sieve synthesized according to the conventional hydrothermal method, 1.42g of PI and 50 mL of 0.1M NaOH solution evenly, put it into a closed reaction autoclave, react at 170°C for 2h under autogenous pressure, and cool with tap water. After filtering, washing, drying at 100°C overnight, calcining at 550°C for 6 hours, 4 After three times of ammonium exchange with Cl, it was calcined again at 550° C. for 6 hours to obtain the mesoporous molecular sieve of the present invention. Its BET specific surface area is 535 square meters per gram, and the outer specific surface is 245 square meters per gram, and the X-ray diffraction spectrum of the product has figure 1 characteristics; the adsorption-desorption spectrum of low-temperature nitrogen adsorption has figure 2 characteristics; transmission electron microscope photos have image 3 Characteristics.

Embodiment 3

[0024] Mix the reaction mixture of 1 g of MCM-22 molecular sieve synthesized by conventional hydrothermal method, 1.42 g of PI and 50 mL of 0.1M NaOH solution evenly, put it into a closed reaction autoclave, react at 170 ° C for 8 h under autogenous pressure, and cool with tap water. After filtering, washing, drying at 100°C overnight, calcining at 550°C for 6 hours, 4 After three times of ammonium exchange with Cl, it was calcined again at 550° C. for 6 hours to obtain the mesoporous molecular sieve of the present invention. Its BET specific surface area is 530 square meters per gram, and the outer specific surface is 243 square meters per gram, and the X-ray diffraction spectrum of the product has figure 1 characteristics; the adsorption-desorption spectrum of low-temperature nitrogen adsorption has figure 2 characteristics; transmission electron microscope photos have image 3 Characteristics.

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Abstract

The invention discloses a method for preparing a mesoporous MCM-22 silicon aluminum molecular sieve, which comprises the following steps: uniformly mixing the MCM-22 molecular sieve synthesized by a conventional hydrothermal method, an organic amine and 0.1M NaOH solution, filling in an enclosed reaction vessel, reacting under the self-generated pressure of 170 DEG for 1-24 hours, cooling the products, filtering, washing, drying, roasting at the temperature of 550 DEG C for 6 hours, exchanging by NH4Cl, roasting at the temperature of 550 DEG C for 6 hours again to obtain the mesoporous MCM-22 silicon aluminum molecular sieve. According to the invention, the intragranular mesoporous is introduced in the MCM-22 structure, thereby an intrastratal decacyclic sine pore and an inner part of an interlayer supercage are communicated, and the internal diffusion limitation can be improved. According to the invention, during the process of melt silicon by alkali treatment, an organic amine stable skeleton is employed, and the crystallization degree of the molecular sieve can be better maintained when the mesoporous can be prepared. The molecular sieve of the present invention is used for macro-molecule reaction, such as an alkylation reaction of benzene and isopropanol, compared with conventional MCM-22, the catalytic activity and the selectivity can be greatly enhanced, and the deactivation rate can be obviously slowed.

Description

technical field [0001] The invention relates to the preparation of mesoporous molecular sieves, in particular to a preparation method of mesoporous MCM-22 silicon-aluminum molecular sieves with MWW crystal structure. Background technique [0002] Zeolite molecular sieves are often used as catalysts in petrochemical production processes such as cracking, hydroisomerization, alkylation, esterification and oxidation reactions. Their narrow pores and size are similar to the molecules used in these petrochemical processes, giving them shape-selective catalytic properties for reactants, products, and intermediates. However, since these narrow micropores are smaller than 1 nm, the diffusion of molecules from the surface to the center of the crystal is a slow process. Therefore, the adsorption and reaction mainly occur on the outer surface of the zeolite, while the inner pores are difficult to utilize, resulting in the total loss of molecular sieve catalysts. The effective utilizat...

Claims

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Application Information

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IPC IPC(8): C01B39/04
Inventor 吴鹏纪永军张坤王达锐蒋金刚季澎
Owner EAST CHINA NORMAL UNIV
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