Preparation method of ZSM-5 molecular sieve

A technology of ZSM-5 and ZSM-11, applied in the field of preparation of ZSM-5, can solve the problems of long reaction time, loss of structure-oriented effect of template agent, etc.

Active Publication Date: 2014-06-11
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method still requires a relatively long reaction time, and due to the loss of the structure-guiding effect of the template, the properties of the system gel and crystallization conditions play an important role in the synthesis.

Method used

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  • Preparation method of ZSM-5 molecular sieve
  • Preparation method of ZSM-5 molecular sieve
  • Preparation method of ZSM-5 molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Prepare the following two mixtures under stirring conditions:

[0038] Mixture I: 19.8g silica sol (40%SiO 2 , 60%H 2 O, the same below), 20g of deionized water were added to the beaker and mixed evenly; then 0.52g (accounting for 5% of the total mass of the raw material silicon aluminum oxide) of hierarchical porous nanorods with a grain size of about 7 μm were added to plug ZSM-11 Molecular sieve powder as seed crystal ( figure 1 a), stir vigorously for 0.5h;

[0039] Mixture II: a homogeneous solution prepared with 1.17g of aluminum sulfate, 1.32g of sodium hydroxide and 15g of deionized water;

[0040] Under the condition of constant stirring, slowly add the mixture II to the mixture I, continue stirring until homogeneous. The resulting reaction mixture has a mass ratio of Na 2 O: Al 2 o 3 :SiO2 2 :H 2O=9.0:1.0:75:1500, transfer the obtained initial gel to a reaction kettle with a polytetrafluoroethylene liner, seal it and let it age at room temperature for...

Embodiment 2

[0043] Under stirring conditions, prepare the following two working solutions respectively:

[0044] Mixture I: Add 11.73g silica sol and 25g deionized into a beaker and mix well. Then add 0.26g (accounting for 5% of the total mass of the raw material silicon-aluminum oxide) hierarchically porous nanorods with a grain size of about 7 μm plugged with ZSM-11 molecular sieve powder as a seed crystal, and stir vigorously for 0.5h;

[0045] Mixture II: a homogeneous solution prepared by 0.26g aluminum sulfate, 0.34g sodium hydroxide and 10g deionized water

[0046] Under continuous stirring, slowly add solution II to solution I, and continue stirring until uniform. The molar ratio of the initial gel is Na 2 O: Al 2 o 3 :SiO2 2 :H 2 O=10.6:1.0:200:6000. After sealing, it was aged at room temperature for 48 hours, and then placed in an oven for static crystallization at 170°C for 6 hours. The obtained product is ZSM-5 molecular sieve with a crystallinity of 108.76%, a hexagon...

Embodiment 3

[0048] Under stirring conditions, prepare the following two working solutions respectively:

[0049] Solution I: Add 15.00g of silica sol and 20g of deionized solution into a beaker and mix well. Then add 0.55g (accounting for 5% of the total mass of the raw material silicon-aluminum oxide) of hierarchically porous nanorods with a grain size of about 7 μm plugged with ZSM-11 molecular sieve powder as a seed crystal, and stir vigorously for 0.5h;

[0050] Solution II: a homogeneous solution prepared by 1.90g aluminum sulfate, 3.14g sodium hydroxide and 15g deionized water

[0051] Under continuous stirring, slowly add solution II to solution I, and continue stirring until uniform. The molar ratio of the initial gel is Na 2 O: Al 2 o 3 :SiO2 2 :H 2 O=13.2:1.0:35:875. After sealing, it was aged at room temperature for 48 hours, and then placed in an oven for static crystallization at 170°C for 24 hours. The obtained product is ZSM-5 molecular sieve with a crystallinity of...

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Abstract

The invention discloses a preparation method of a ZSM-5 molecular sieve. The preparation method comprises the following steps: (1) mixing a substance containing elements in the IVA group, a substance containing elements in the IIIA group, alkali metal hydroxides, a crystal seed, and water so as to obtain a gel liquid; (2) carrying out an aging treatment on the gel liquid obtained in the step (1) for 0 to 240 hours; (3) crystallizing the aged mixture at a temperature of 120 to 180 DEG C so as to obtain the ZSM-5 molecular sieve; wherein the crystal seed is a ZSM-11 molecular sieve having a grafted nanotube shape. The preparation method is carried out in a template-free system, and utilizes a ZSM-11 molecular sieve, whose phase is different from that of target ZSM-5 molecular sieve, to prepare a ZSM-5 molecular; thus the morphology and size of the obtained ZSM-5 molecular sieve can be controlled just through adjusting the morphology of ZSM-11 molecular sieve taken as the crystal seed, the ZSM-5 molecular sieve has a pure phase and a high crystallization degree, and the crystallization speed of the preparation method is faster than that of conventional methods taking ZSM-5 as the crystal seed.

Description

technical field [0001] The present invention relates to a method for preparing ZSM-5, in particular to a method for rapidly synthesizing ZSM-5 molecular sieves with controllable morphology and size in a template-free system using ZSM-11 as a seed crystal. Background technique [0002] ZSM-5 molecular sieve is a member of the pentasil family of high silicon shape selective molecular sieves. A three-dimensional channel system with a cross, which is composed of a zigzag with a corner of 150° and a linear ten-membered ring channel. )between. Due to the hydrophobicity caused by the high silicon-aluminum ratio in its skeleton and its special pore structure and acid distribution, it has high shape selectivity and anti-coking performance, and is widely used in the aromatization of hydrocarbons , catalytic cracking and isomerization and other petrochemical processes. As an active component for increasing the production of low-carbon olefins, due to its special pore structure, ZSM-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/38
Inventor 李春义于庆君
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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