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Method for one step synthesis of hierarchical porous structured ZSM-5 zeolite with open pores

A technology of ZSM-5 and pore structure, applied in the direction of crystalline aluminosilicate zeolite, borocarbane silicone crystalline aluminosilicate zeolite, etc., can solve the problem of ZSM-5 zeolite molecular sieve diffusion and non-multilevel pore structure properties, non-openness, etc., to avoid the use of a large number of structure-directing agents, to have a bright prospect for industrial application, and to reduce the cost of preparation

Active Publication Date: 2015-07-08
江苏黄马化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Patent CN201210500363.2 discloses a method for preparing ZSM-5 molecular sieve without template; The technical scheme of synthesizing ZSM-5 zeolite under certain conditions, its micropores have good openness, and can be exchanged without roasting, but the ZSM-5 molecular sieve crystals obtained by the template-free method are generally large and do not have multi-level Pore ​​structure properties, so it cannot solve the problem of limited diffusion of ZSM-5 zeolite molecular sieve in practical application
Whether it is a hard template method, a soft template method or a single small molecule template assembly method, the hierarchical pore structure ZSM-5 zeolite, its micropores are filled with a structure-directing agent, which is not open, and needs to be calcined to remove the template agent. Release the micropore channels, and the process of roasting to remove the template agent often causes environmental pollution

Method used

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  • Method for one step synthesis of hierarchical porous structured ZSM-5 zeolite with open pores
  • Method for one step synthesis of hierarchical porous structured ZSM-5 zeolite with open pores
  • Method for one step synthesis of hierarchical porous structured ZSM-5 zeolite with open pores

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Experimental program
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Effect test

Embodiment 1

[0020] a. Preparation of Active Colloidal Seed Crystals

[0021] Get 43 grams of tetraethyl orthosilicate and 60 grams of tetrapropyl ammonium hydroxide aqueous solution that content is 25 wt% and mix, stir and hydrolyze at room temperature, after hydrolysis is complete, in 100 o Aged at C for 24 hours, the product was active colloidal seed crystal I.

[0022] B, the preparation of ZSM-5 zeolite

[0023] 1.67 grams of aluminum sulfate octadecahydrate and 1.05 grams of concentration are 98% sulfuric acid dissolved in 40 grams of water, and the solution obtained is slowly added dropwise to 22.2 grams of water glass and mixed (the silicon oxide content in the water glass is 27.1 wt%; Sodium oxide content is 8.38 wt%), get 0.25 gram above-mentioned active colloidal seed crystal I and add in this synthesis system, stir at room temperature for 2 hours, then at 175 o C was crystallized for 24 hours, and after filtration, the aggregate product of mesoporous structure formed by the a...

Embodiment 2

[0036] a. Preparation of Active Colloidal Seed Crystals

[0037] Get 30 grams of silicon oxide content and be that the silica sol of 30% is mixed with the tetrapropyl ammonium hydroxide aqueous solution of 25 wt % with 43 grams of content, stir and hydrolyze at room temperature for 2 hours, then at 80 o C temperature for 72 hours, the product was active colloidal seed crystal II.

[0038] B, the preparation of ZSM-5 zeolite

[0039] 1.67 grams of aluminum sulfate octadecahydrate and 1.05 grams of concentration are 98% sulfuric acid dissolved in 40 grams of water, and the solution obtained is slowly added dropwise to 22.2 grams of water glass and mixed (the silicon oxide content in the water glass is 27.1 wt%; Sodium oxide content is 8.38 wt%), get 0.025 gram of active colloidal seed crystal II prepared above and add in this synthesis system, stir at room temperature for 2 hours, then at 175 o C was crystallized for 24 hours, and after filtration, a mesoporous aggregate forme...

Embodiment 3

[0042] 0.45 gram of aluminum sulfate octadecahydrate and 2 gram of concentration are 98% sulfuric acid dissolved in 40 gram of water, the solution obtained is slowly added dropwise to 22.2 gram of water glass and mixed (the silicon oxide content in the water glass is 27.1 wt%; Sodium oxide content is 8.38 wt%), the active colloidal seed crystal I that gets 0.5 gram above-mentioned embodiment 1 preparations adds in this synthesis system, stirs at room temperature 2 hours, then at 175 o C was crystallized for 24 hours and then filtered to obtain a mesoporous aggregate formed by the accumulation of nanoparticles, which is a ZSM-5 zeolite with open micropores and hierarchical pore structures. The silica / alumina molar ratio of the synthesis system is 150; the sodium oxide / silica molar ratio is 0.08; the water / silica molar ratio is 30; the silica in the colloidal seed accounts for 1% of the total silica in the synthesis system wt%, where the molar ratio of tetrapropylammonium hydrox...

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Abstract

The invention discloses a method for one step synthesis of hierarchical porous structured ZSM-5 zeolite with open pores. The method is characterized in that active colloidal crystal seeds are introduced to a reaction system composed of an inorganic silicon source and an aluminum source in order to realize one step synthesis of the hierarchical porous structured ZSM-5 zeolite with open pores, and the colloidal crystal seeds are prepared through the steps of mixing tetramethyl orthosilicate, tetraethyl orthosilicate or silica sol with a template, hydrolyzing and ageing; and the template is tetrapropylammonium hydroxide or tetrapropylammonium bromide. Compared with zeolite in the prior art, the hierarchical porous structured ZSM-5 zeolite with open pores has accumulated meso-porous properties, has a meso-pore volume approaching 0.3ml / g and an external surface area approaching 100m<2> / g, can realize ion exchange without roasting, well avoids the use of a large amount of a structure directing agent, and has reduced preparation cost; and the method also has the advantages of simplicity, environmental protection, high efficiency, certain industrialization utilization prospect, and substantial economy value.

Description

technical field [0001] The invention relates to the technical field of molecular sieve synthesis, in particular to a method for synthesizing ZSM-5 zeolite with a multi-level pore structure with open channels in one step. Background technique [0002] ZSM-5 is a silica-alumina zeolite with MFI topology, which was first invented by the Mobil Petroleum Company of the United States in 1972 (US3702886), because of its good thermal and hydrothermal stability, controllable acid amount and acid strength and unique The pore structure and shape selectivity are widely used in petroleum refining, petrochemical and fine chemical industries. [0003] ZSM-5 zeolite has straight shape and zigzag channel of ten-membered ring, and the diameter of straight channel is 0.51 × 0.55 nm, zigzag channel aperture 0.54 × 0.56 nanometers, smaller pores are conducive to shape-selective catalysis, but in some reactions involving macromolecules, relatively small pores are not conducive to the diffusi...

Claims

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Application Information

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IPC IPC(8): C01B39/40
Inventor 薛腾吴海虹何鸣元
Owner 江苏黄马化工有限公司
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