Hollow molecular sieve, and preparation method and application thereof

A molecular sieve and hollow technology, applied in the field of molecular sieves, can solve problems such as limiting the practical application of molecular sieves, achieve the effects of solving diffusion problems, low preparation costs, and simple methods

Active Publication Date: 2016-11-09
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, the preparation of hierarchical molecular sieves with short diffusion channels and tunable acid site distribution is still a challenge, thus severely limiting the practical applications of molecular sieves.

Method used

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  • Hollow molecular sieve, and preparation method and application thereof
  • Hollow molecular sieve, and preparation method and application thereof
  • Hollow molecular sieve, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The preparation method of ZSM-5 type hollow molecular sieve comprises the steps:

[0031] 1) Ethyl orthosilicate, tetrapropylammonium hydroxide, Al(NO 3 ) 3 9H 2 O and H 2 O was mixed at a molar ratio of 1:0.1:0:20, stirred thoroughly, and hydrothermally crystallized; the product was centrifuged and washed to obtain a gel containing ZSM-5, which was used as a seed crystal for future use. The structure of the seed crystal was as follows: figure 1 shown;

[0032] 2) Ethyl orthosilicate, tetrapropylammonium hydroxide, Al(NO 3 ) 3 9H 2 O and H 2 O is mixed at a molar ratio of 1:1:0.125:600, and after being fully stirred, a ZSM-5 growth solution is obtained; then the seed crystal prepared in step 1) is added to the ZSM-5 growth solution, and the seed crystal and the ZSM-5 molecular sieve grow The mass ratio of the solution is 1:200, hydrothermal crystallization; the crystallized product is centrifuged, washed, dried, and roasted to obtain a ZSM-5 molecular sieve whos...

Embodiment 2

[0036] The preparation method of ZSM-5 type hollow molecular sieve comprises the steps:

[0037] 1) Ethyl orthosilicate, tetrapropylammonium hydroxide, Al(NO 3 ) 3 9H 2 O and H 2 O was mixed at a molar ratio of 1:0.5:0.125:100, stirred thoroughly, hydrothermally crystallized; the product was centrifuged and washed to obtain a gel containing ZSM-5, which was used as a seed crystal for later use;

[0038] 2) Ethyl orthosilicate, tetrapropylammonium hydroxide, Al(NO 3 ) 3 9H 2 O and H 2 O is mixed in a molar ratio of 1:0.25:0:200, and after fully stirring, a ZSM-5 growth solution is obtained; then the seed crystal prepared in step 1) is added to the ZSM-5 growth solution, the seed crystal and the ZSM-5 molecular sieve growth solution The mass ratio is 1:50, hydrothermal crystallization; the crystallized product is centrifuged, washed, dried, and roasted to obtain a ZSM-5 molecular sieve whose core-shell is composed of different Si / Al ratio structures;

[0039] 3) Add the ...

Embodiment 3

[0042] The preparation method of ZSM-5 type hollow molecular sieve comprises the steps:

[0043] 1) Ethyl orthosilicate, tetrapropylammonium hydroxide, Al(NO 3 ) 3 9H 2 O and H 2 O was mixed at a molar ratio of 1:0.2:0.04:50, stirred thoroughly, and hydrothermally crystallized; the product was centrifuged and washed to obtain a gel containing ZSM-5, which was used as a seed crystal for later use;

[0044] 2) Ethyl orthosilicate, tetrapropylammonium hydroxide, Al(NO 3 ) 3 9H 2 O and H 2 O is mixed with a molar ratio of 1:0.8:0.08:500, and after being fully stirred, a ZSM-5 growth solution is obtained; then the seed crystal prepared in step 1) is added to the ZSM-5 growth solution, the seed crystal and the ZSM-5 molecular sieve growth solution The mass ratio is 1:100, hydrothermal crystallization; the crystallized product is centrifuged, washed, dried, and roasted to obtain a ZSM-5 molecular sieve whose core-shell is composed of different Si / Al ratio structures;

[0045]...

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Abstract

The invention provides a hollow molecular sieve, and a preparation method and application thereof. The hollow molecular sieve has an external diameter of 50 nm to 10 [mu]m, an internal diameter of 20 nm to 9 [mu]m, and a specific surface area of 200 to 1000 m<2> / g; the shell of the hollow molecular sieve is composed of three layers of isomorphous molecular sieves with different Si / Al ratios; and the hollow molecular sieve may be one or more selected from a group consisting of a ZSM-5 type hollow molecular sieve, a beta type hollow molecular sieve and a Y type hollow molecular sieve. The hollow molecular sieve can effectively overcome the problem of diffusion in practical application; the size and shell thickness of the hollow molecular sieve can be regulated by changing a feed ratio and crystallization conditions; and a super-weak-solution-phase epitaxial growth method used in the invention is simple, has a wide application scope, can prepare three layers of isomorphous molecular sieve structures with different Si / Al ratios in a shell structure, is applicable to ZSM-5, beta and Y type molecular sieves and has low preparation cost.

Description

technical field [0001] The invention relates to the technical field of molecular sieves, in particular to a hollow molecular sieve, a preparation method and an application thereof. Background technique [0002] Paraxylene (PX) is one of the aromatic hydrocarbons with the largest amount of consumption. There is a large gap between supply and demand, and it is difficult to achieve self-sufficiency. The methanol aromatization technology can not only expand the downstream application of methanol, but also help to improve the current situation of excess methanol, and can obtain Aromatic products with high single-pass yield and relatively simple composition will significantly reduce the cost and technical difficulty in the separation and purification steps compared with petroleum routes. [0003] The methanol aromatization reaction generally adopts ZSM-5 molecular sieve with the best shape-selective effect of aromatics as a catalyst. Conventional molecular sieves are often diffic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04C01B39/24C01B39/40B01J29/40B01J29/08B01J29/70C07C1/20C07C15/08
CPCY02P20/52C01B39/40B01J29/088B01J29/405B01J29/7057C01B39/04C01B39/24C07C1/20C07C2529/08C07C2529/40C07C2529/70C07C15/08
Inventor 骞伟中王宁魏飞
Owner TSINGHUA UNIV
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