Nano-beta molecular sieve with low Si/Al ratio and preparation method thereof

A beta molecular sieve and molecular sieve technology, applied in the field of preparation of nano beta molecular sieve, can solve the problems of aggravated coking and deactivation, and achieve the effects of inhibiting coking, reducing usage, and reducing synthesis cost.

Active Publication Date: 2010-06-09
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reduction of silicon-aluminum ratio by large-grained molecular sieves will inevitably lead to increased coking and rapid deactivation

Method used

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  • Nano-beta molecular sieve with low Si/Al ratio and preparation method thereof
  • Nano-beta molecular sieve with low Si/Al ratio and preparation method thereof
  • Nano-beta molecular sieve with low Si/Al ratio and preparation method thereof

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preparation example Construction

[0024] (1) Preparation of reaction mixture gel

[0025] Add the FAU molecular sieve to the template agent (tetraethylammonium bromide) aqueous solution with a concentration of 0.4~3mol / L, the solid-liquid ratio of the FAU molecular sieve and the template solution is 1g: (4~20)mL, stir evenly, and then Add a small amount of concentrated ammonia water, the volume of which accounts for 6-12% of the volume of the template solution, and stir for 1-4 hours. Then add the silicon source, stir evenly, and make a reaction mixture gel, and the final molar ratio of each component is as follows: (3-25) SiO 2 :Al 2 o 3 : (1~4)Na 2 O:(2~10)TEABr:(100~600)H 2 O.

[0026] The FAU molecular sieve described here includes NaX molecular sieve and NaY molecular sieve with low silicon-aluminum ratio, and the silicon-aluminum ratio of the FAU molecular sieve is 1.02-2.6. The silicon source is selected from white carbon black, silica sol or a mixture of the two.

[0027] (2) Crystallization

...

Embodiment 1

[0033]Firstly, 9 g of NaX molecular sieve (Si / Al molar ratio is 1.1) is added into 120 mL of tetraethylammonium bromide aqueous solution (concentration is 1 mol / L), and stirred evenly. Then 7 mL of concentrated ammonia water was added to the above solid-liquid mixture, and stirred for 3 hours. Then add 35mL silica sol (w(SiO 2 )=30%) and stir evenly. The mixture was transferred into an autoclave for hydrothermal crystallization at 140°C for 48 hours. The resulting product was centrifuged and washed with distilled water until neutral. Finally, the obtained solid was dried at 100° C. for 12 hours to obtain nano-β molecular sieves.

[0034] The XRD spectrogram and scanning electron micrograph of this nanometer β molecular sieve are as figure 1 , 2 shown. from figure 1 It can be seen that the characteristic peaks of β molecular sieves are quite obvious. from figure 2 It can be seen that the grain size of β molecular sieve is mostly concentrated between 120 and 200 nm, an...

Embodiment 2

[0036] First, add 10 g of NaX (Si / Al molar ratio is 1.1) into 120 mL aqueous solution of tetraethylammonium bromide (concentration: 1.1 mol / L), and stir evenly. Then 7 mL of concentrated ammonia water was added to the above solid-liquid mixture, and stirred for 3 hours. Then add 45mL silica sol (w(SiO 2 )=30%) and stir evenly. The mixture was transferred into an autoclave for hydrothermal crystallization at 137°C for 45 hours. The resulting product was centrifuged and washed with distilled water until neutral. Finally, the obtained solid was dried at 100° C. for 12 hours to obtain nano-β molecular sieves.

[0037] The XRD spectrogram and scanning electron micrograph of this nanometer β molecular sieve are as image 3 , 4 shown. from image 3 It can be seen that the characteristic peaks of β molecular sieves are quite obvious. from Figure 4 It can be seen that the grain size of β molecular sieve is mostly concentrated between 100-140nm, and the grain shape is spherica...

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Abstract

The invention relates to a nano-beta molecular sieve with low Si / Al ratio and a synthesis method thereof. The method uses a low-cost microporous molecular sieve of FAU configuration as an aluminum source to synthesize the nano-beta molecular sieve under the condition of adding a conventional silicon source and a non-toxic cheap template agent. The Si / Al molar ratio of a framework of the nano-beta molecular sieve is between 4 and 9, grains are spherical or cuboidal, and the grain size is between 30 and 200nm. Due to the two characteristics of low Si / Al ratio and nanoscale grain size, the nano-beta molecular sieve can remarkably improve catalytic activity and inhibit the generation of coking at the same time. A raw material, namely the FAU molecular sieve adopted by the method has lower cost, so the method is particularly suitable for industrial mass production and industrial application.

Description

technical field [0001] The invention relates to a nano molecular sieve and a preparation method thereof, in particular to a preparation method of a nano β molecular sieve. Background technique [0002] β molecular sieve is a microporous molecular sieve with a twelve-membered ring and a large pore size. In 1967, Mobil Corporation announced its synthesis method for the first time, and since then many researchers have carried out a lot of synthesis research work. The traditional synthesis method of β molecular sieve is based on Na 2 O-SiO 2 -Al 2 o 3 -H 2 O-R reaction mixture hydrothermal synthesis. β molecular sieve has good thermal and hydrothermal stability, moderate acidity and acid stability, and hydrophobicity. It is not easy to coke and has a long service life in catalytic reactions. [0003] Nanoparticles refer to particles with a particle diameter ranging from 0.1 nm to 100 nm. Nano-molecular sieves, as a new type of nano-materials, have attracted much attentio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/00
Inventor 张志智凌凤香孙万付张喜文秦波王少军
Owner CHINA PETROLEUM & CHEM CORP
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