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Method for synthesizing MCM-49 type zeolite molecular sieve under condition of no organic template agent

A technology of MCM-49 and zeolite molecular sieves, which is applied in the field of synthesizing MCM-49 zeolite molecular sieves, can solve problems such as pollution and increase the production cost of zeolite catalysts

Inactive Publication Date: 2021-03-16
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the one hand, the use of organic templates greatly increases the production cost of zeolite catalysts. On the other hand, harmful gases are released during the calcination process of zeolite, which pollutes the environment. Therefore, synthesis without organic templates is a challenge for the preparation of MCM-49 molecular sieves.

Method used

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  • Method for synthesizing MCM-49 type zeolite molecular sieve under condition of no organic template agent
  • Method for synthesizing MCM-49 type zeolite molecular sieve under condition of no organic template agent
  • Method for synthesizing MCM-49 type zeolite molecular sieve under condition of no organic template agent

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preparation example Construction

[0043] As a preferred embodiment, the synthesis method of the seed crystal comprises:

[0044] S201a, form a silica-alumina gel under stirring and mixing at room temperature through an alkali metal oxide source, an alumina source, and a silica source, so that the silica-alumina gel has the following molar ratio relationship: Na 2 O / SiO 2 =0.15~0.25, SiO 2 / Al 2 o 3 =25~35,H 2 O / SiO 2 =25~50, HMI / SiO 2 =0.5~0.6;

[0045] S202a. Aging and crystallizing the above-mentioned silica-alumina gel to obtain a seed crystal product, cooling the seed crystal product to room temperature, washing to neutrality, drying and calcining to obtain MCM-49 Zeolite molecular sieve seeds.

[0046] As a preferred embodiment, the synthesis method of the seed crystal comprises:

[0047] S201b, form a silica-alumina gel under stirring and mixing at room temperature through an alkali metal oxide source, an alumina source, and a silica source, so that the silica-alumina gel has the following molar...

Embodiment 1

[0057] A method for synthesizing an MCM-49 type zeolite molecular sieve without an organic template, comprising the steps of:

[0058] Dissolve 0.3284g of sodium metaaluminate and 0.1344g of sodium hydroxide in 21.6g of water. After dissolving, add 6g of silica sol to the above solution, and form a silica-alumina gel after stirring for about 1 hour; put the above gel into a Aged for 12 hours at 50°C in a stainless steel reaction kettle lined with polytetrafluoroethylene. Add 0.15g SiO 2 / Al 2 o 3 =25-35 MCM-49 molecular sieve seed crystals were added to the above-mentioned silica-alumina gel, and the stirring was continued at room temperature for 10-15 minutes. Crystallize at 150°C for 3 days; after cooling, filter at room temperature to obtain the crystallized product; naturally cool the crystallized product to room temperature, and then wash the crystallized product in a centrifuge with a centrifugal speed of 8000-12000r / min for 1- 3 times, then dried, and finally calcin...

Embodiment 2

[0065] A method for synthesizing an MCM-49 type zeolite molecular sieve without an organic template, comprising the steps of:

[0066] Dissolve 0.2463g of sodium metaaluminate and 0.0344g of sodium hydroxide in 5.9417g of water. After dissolving, add 6.9519g of water glass into the above solution, stir for about 1 hour to form a silica-alumina gel, and put the above gel into Aged for 12 hours at 80°C in a stainless steel reaction kettle lined with polytetrafluoroethylene. Add 0.15g SiO 2 / Al 2 o 3 =25-35 MCM-49 molecular sieve seed crystals were added to the above-mentioned silica-alumina gel, and the stirring was continued at room temperature for 10-15 minutes. Crystallize at 150°C for 5 days; after cooling, filter at room temperature to obtain the crystallized product; naturally cool the crystallized product to room temperature, and then wash the crystallized product in a centrifuge with a centrifugal speed of 8000-12000r / min for 1- 3 times, then dried, and finally calci...

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Abstract

The invention provides a method for synthesizing an MCM-49 type zeolite molecular sieve under the condition of no organic template agent. Silica-alumina gel is formed by stirring and mixing an alkalimetal oxide source, an aluminum oxide source and a silicon dioxide source at room temperature, so that the composition of the silica-alumina gel has the following molar ratio relationship: Na2O / SiO2 =0.017-0.19, SiO2 / Al2O3 = 10-50, and H2O / SiO2 = 3-15. The preparation method comprises the following steps: carrying out aging treatment on silica-alumina gel, adding the MCM-49 type zeolite molecularsieve as a seed crystal, and carrying out hydrothermal treatment to obtain a crystal product; and cooling the product at room temperature, washing to be neutral, drying and calcining to obtain MCM-49type zeolite molecular sieve powder. According to the synthesis method provided by the invention, an organic template agent does not need to be added, so that the environmental pollution caused by hexamethylene imine is avoided while the cost is reduced. The MCM-49 type zeolite molecular sieve product obtained by the method provided by the invention can be used as a seed crystal and can be continuously used in a new round of MCM-49 type molecular sieve synthesis process.

Description

technical field [0001] The invention belongs to the technical field of molecular sieve synthesis, and in particular relates to a method for synthesizing an MCM-49 type zeolite molecular sieve under the condition of no organic template agent. Background technique [0002] In 1993, Bennett et al. reported the synthesis of MCM-49 molecular sieves. MCM-49 molecular sieve is the first directly synthesized MWW layered structure molecular sieve without precursor calcination. There are differences in the distribution of aluminum and framework aluminum. Lawton et al. believed that the c-axis parameter of the unit cell of MCM-49 was longer than that of MCM-22, and speculated that this may be related to the different distribution of aluminum in the framework of the two. The content of interlayer templating agent in MCM-22 is higher than that in MCM-49, and the content of framework aluminum in MCM-49 is higher than that in MCM-22. Due to its unique pore structure, MCM-49 molecular si...

Claims

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Application Information

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IPC IPC(8): C01B39/46
CPCC01B39/46C01P2002/72C01P2004/03
Inventor 王卓鹏熊凌燕
Owner NORTHEASTERN UNIV
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