Multi-level pore channel molecular sieve preparation method

A microporous molecular sieve and molecular sieve technology are applied in the field of preparation of multi-stage porous molecular sieves, which can solve the problems of increased cost, complicated operation process, strong corrosiveness and the like, and achieve the effect of simplifying the process.

Inactive Publication Date: 2016-01-13
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the use of NaOH solution as the alkali source has strong corrosiveness, and the use of organic alkalis leads to increased costs
In addition, in the molecular sieve with hierarchical pore structure prepared by the above method, the cation that balances the negative charge of the framework is Na + , when used in acid-catalyzed reactions, it must undergo liquid-phase ion exchange, water washing, filtration, drying and roasting before it can be converted into H-type, and the operation process is cumbersome.

Method used

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  • Multi-level pore channel molecular sieve preparation method
  • Multi-level pore channel molecular sieve preparation method
  • Multi-level pore channel molecular sieve preparation method

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Effect test

Embodiment 1

[0019] Take Beta molecular sieve with Si / Al=19, mix it with 10wt.% urea solution according to the ratio of 1g:100mL, and stir and react for 5h under the condition of back distillation. Suction filtration, washing with deionized water, drying, 550 o C roasting for 5 hours to obtain micro-mesoporous molecular sieves, that is, multi-level channel Beta molecular sieves.

[0020] The X-ray diffraction pattern (XRD) of the obtained sample is shown in the attached figure 1 , the TEM image is shown in the appendix figure 2 , the mesopore size distribution is shown in the attached image 3 , NH 3 -TPD diagram see attached Figure 4 . The specific surface area of ​​the obtained sample is 452m 2 / g, total pore volume 0.34cm 3 .g -1 , mesopore volume 0.18cm 3 .g -1 , the BJH pore size distribution of the mesopores is 3-22nm, and the mesopore diameter of the concentrated distribution is 11nm.

Embodiment 2

[0022] Take Beta molecular sieve with Si / Al=55, mix it with 20wt.% urea solution according to the ratio of 1g:20mL, and stir and react for 10h under the condition of back distillation. Suction filtration, washing with deionized water, drying, 550 o C roasting 5h. Finally, a micro-mesoporous molecular sieve is obtained. The specific surface area of ​​the obtained sample is 438m 2 / g, total pore volume 0.37cm 3 .g -1 , mesopore volume 0.22cm 3 .g -1 , the BJH pore size distribution of the mesoporous is 4-32nm, and the mesopore pore size of the concentrated distribution is 14nm.

Embodiment 3

[0025] Get the Beta molecular sieve of Si / Al=19, mix with 10wt.% urea solution according to the ratio of 1g:100mL, at 80 o C stirred the reaction for 5h. Suction filtration, washing with deionized water, drying, 550 o C roasting 5h. Finally, a micro-mesoporous molecular sieve is obtained. The specific surface area of ​​the obtained sample is 473m 2 / g, total pore volume 0.33cm 3 .g -1 , mesopore volume 0.17cm 3 .g -1 , The BJH pore size distribution of the mesoporous is 3-18nm, and the pore size of the concentrated mesopore is 8nm.

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Abstract

The invention relates to a new multi-level pore channel molecular sieve preparation method, and belongs to the technical field of inorganic porous materials. According to the method, the urea solution is used to replace the NaOH solution or organic alkali solution as the desilication reagent, the amount of NH3 generated in an in-situ manner is controlled by using the urea solution concentration, the reaction temperature and the reaction time, the pH value of the reaction slurry during the process is constant, and the method is the economic, environmental protection and convenient post-treatment method. According to the present invention, the prepared multi-level pore channel molecular sieve can well maintain the relative crystallinity, the micro-pore pore volume and most of the acid characteristics of the original molecular sieve; and the obtained sample can be directly used for the acid-catalyzed reaction without NH4<+> ion exchange and subsequent water washing, drying and calcination process, such that the process is substantially simplified.

Description

technical field [0001] The invention relates to a new method for preparing a multi-stage pore molecular sieve, which belongs to the technical field of inorganic porous materials. Background technique [0002] Microporous zeolite molecular sieves are widely used in various industrial processes such as catalysis and separation due to their high specific surface area, uniform pore structure, strong acid properties, and good thermal and hydrothermal stability. However, its microporous nature limits its application in reactions related to macromolecules, with consequences such as low catalytic activity and easy deactivation due to diffusion limitation. In order to overcome this shortcoming of microporous molecular sieves, researchers began to introduce mesopores into microporous molecular sieves to prepare multi-level pore molecular sieves to weaken the diffusion limitation and enhance stability. [0003] The synthesis method of multi-stage pore molecular sieve includes in-situ ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/38C01B39/42
Inventor 田福平曹春晓胡敏张少峰
Owner DALIAN UNIV OF TECH
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