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Method for synthesizing ZSM-5/Silicalite core-shell molecular sieve by using vapor phase process

A synthesis method, the technology of ZSM-5, is applied in the direction of molecular sieve characteristic polymorphic crystalline silicon, silicon compounds, silicon dioxide, etc., which can solve the problems of difficult environmental impact treatment of template agents, low product shell coverage, etc. The effect of technical effects

Active Publication Date: 2015-04-29
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The technical problem to be solved by the present invention is that existing epitaxial growth method synthesis core-shell molecular sieve technology exists in the low product shell coverage, the template agent is difficult to deal with the environmental impact, etc., to provide a new gas phase method to synthesize ZSM-5 / Silicalite-1 core-shell molecular sieve method

Method used

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  • Method for synthesizing ZSM-5/Silicalite core-shell molecular sieve by using vapor phase process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add 20 grams of TEOS to 55 grams of water and hydrolyze for 8 hours to form solution A. Add 10 grams of ZSM-5 molecular sieve (nuclear phase silicon-aluminum ratio = 30, particle size = 0.1 micron) to solution A to form suspension B. Put B in an 80°C water bath and stir for 4 hours to make dry glue C, put C in the upper layer of the crystallization kettle, put 4.56g of TPAOH and 60g of water in the lower layer of the crystallization kettle, and crystallize at 150°C After 2 days, after the crystallization, the solid in the upper layer was washed until the pH was 6-8, and then dried. The obtained sample can be seen through the SEM spectrum. On the outer surface of ZSM-5, fine particles are evenly distributed, and the shell coverage is 90%, which can confirm that the obtained molecular sieve material is ZSM-5 in the core phase and Silicalite-1 in the shell layer. Zeolite ZSM-5 / Silicalite-1 core-shell zeolite molecular sieve. Denoted as core-shell molecular sieve CS1.

...

Embodiment 2

[0027] Add 20 grams of silica sol to 60 grams of water and hydrolyze for 10 hours to prepare solution A. Add 15 grams of ZSM-5 molecular sieve (nuclear phase silicon-aluminum ratio = 30, particle size = 0.5 microns) to solution A to prepare suspension B. Put B in an 85°C water bath and stir for 2 hours to make dry glue C, put C in the upper layer of the crystallization kettle, put 5.23 grams of TPABr and 65 grams of water in the lower layer of the crystallization kettle, and crystallize at 140°C After 3 days, after the crystallization, the solid in the upper layer was washed until the pH was 6-8, and then dried. The obtained sample can be seen through the SEM spectrum. On the outer surface of ZSM-5, fine particles are evenly distributed, and the shell coverage is 85%, which can confirm that the obtained molecular sieve material is ZSM-5 in the core phase and Silicalite-1 in the shell layer. Zeolite ZSM-5 / Silicalite-1 core-shell zeolite molecular sieve. Denoted as core-shell ...

Embodiment 3~15

[0030] Examples 3-15 were synthesized according to the synthesis ratio and synthesis conditions in Table 1, and the core-shell molecular sieves CS3~15# were synthesized according to the similar method and steps of Embodiment 1, see Table 1 for details.

[0031]

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Abstract

The invention relates to a method for synthesizing a ZSM-5 / Silicalite core-shell molecular sieve by using a vapor phase process, mainly solving the technical problems that the product shell layer is low in coverage degree and the influence on the environment caused by a template agent is hard to process in the prior art for synthesizing the core-shell molecular sieve by using an epitaxial growth method. The method for synthesizing the ZSM-5 / Silicalite core-shell molecular sieve by using the vapor phase process comprises the following steps: (a) mixing and stirring a silicon source with water according to a mole ratio of 20-200, and hydrolyzing for 2-24 hours; (b) adding a ZSM-5 nuclear phase molecular sieve into a solution prepared by the step (a), then drying the solution at 100-120 DEG C; (c) putting a solid product prepared by the step (b) in an upper layer of a crystallization kettle, adding a template agent water solution into a lower layer of the crystallization kettle, and crystallizing at 120-180 DEG C for 0.5-5 days; and (d) preparing a ZSM-5 / Silicalite-1 core-shell type zeolite molecular sieve after the crystallization is ended. The method can be applied to industrial production for preparing paraxylene by disproportionating methylbenzene.

Description

technical field [0001] The invention relates to a gas-phase method for synthesizing ZSM-5 / Silicalite-1 core-shell molecular sieves. Background technique [0002] Zeolite molecular sieve is a kind of microporous crystal material with skeleton structure. It has specific size and shape of pore structure, large specific surface area and strong adjustable acidity. It is widely used in the process of petroleum refining and processing. Such as catalytic cracking, alkane isomerization, catalytic reforming and toluene disproportionation and other catalytic reactions. [0003] Since the 1960s Weisz et al [J. JPhys Chem, 1960, 64:382] Since the discovery that small-pore zeolite molecular sieves have shape-selective properties, the research on zeolite molecular sieves and shape-selective catalysis has always been a research hotspot in the field of petrochemical industry. Among them, ZSM-5 molecular sieve is a kind of medium-pore zeolite, and the outer surface or pores of its crystal g...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/38C01B37/02
CPCC01B37/02C01B39/38
Inventor 李为陈秉祁晓岚孔德金
Owner CHINA PETROLEUM & CHEM CORP
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