Preparation method for high-dispersion zeolite molecular sieves

A zeolite molecular sieve and molecular sieve technology, applied in the direction of crystalline aluminosilicate zeolite, etc., can solve the problems of prolonged crystallization time, dispersion, and low hydrothermal stability, and achieve the purpose of inhibiting crystal transformation of the system, reducing condensation and agglomeration, and external specific surface area big effect

Active Publication Date: 2013-07-17
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Materials with zeolite mesoporous composite structure can improve the diffusion properties of products, make up for the deficiency of microporous molecular sieves, and provide a favorable spatial configuration for macromolecular reactions, but their acidity is weak and their hydrothermal stability is relatively low, etc. problem persists
However, when the amount of organic additive added is small, it cannot play a role in dispersing; when the amount is slightly larger, it will seriously hinder the crystallization of mo

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0138] Repeat comparative example 1, water glass (SiO 2 ), water, sulfuric acid, aluminum sulfate (Al 2 o 3 ), isopropanol (IPA) and n-butylamine (NBA) in molar ratio as SiO 2 / Al 2 o 3 =178,OH - / SiO 2 =0.58, NBA / SiO 2 =0.40, IPA / SiO 2 =0.01,H 2 O / SiO 2 =15 prepared into a homogeneous gel, and added its SiO to the gel 2 Total weight 2% ZSM-5 molecular sieve seed crystals. After the reaction gel was emulsified by an emulsifier for 15 minutes, it was transferred to a high-pressure hydrothermal kettle, stirred and aged at 100°C for 24 hours, and then heated to 170°C for crystallization for 23 hours. Wherein 23h is the crystallization end time of the zeolite molecular sieve determined by examining the crystallization curve of the zeolite molecular sieve. When the zeolite molecular sieve crystallization time reaches 23h, trimethylchlorosilane (by mass ratio R / SiO 2 =0.5 meter) into the crystallization kettle with the crystallization compound, stirred evenly, and react...

Embodiment 2

[0140] Repeat implementation 1, but replace trimethylchlorosilane with methyltrichlorosilane and methylhydrogendichlorosilane of the same quality respectively, then the products obtained are proved to be pure ZSM-5 molecular sieves through X-ray diffraction analysis, and their relative crystallinity The degrees are 86% and 90% respectively. Characterized by SEM, the product is dispersed nano zeolite. via N 2 Characterized by physical adsorption, the BET external area is 70m 2 / g, 65m 2 / g, and the product filtration rate is 10 times that of Comparative Example 1.

Embodiment 3

[0142] Repeat Example 1, when the crystallization time of the zeolite molecular sieve reaches 23h, open the pressure reducing valve, so that part of the water, vaporizable isopropanol and n-butylamine in the crystallization material liquid are recovered through condensation, and the recovered liquid can be recycled . Pour trimethylchlorosilane into the kettle filled with the crystallization material liquid after decompression, stir evenly, and react at 100°C for 5h. The obtained solid product is filtered through a plate frame, washed, dried and roasted to obtain pure ZSM-5 molecular sieve. The relative crystallinity of the product is 93.0%. Characterized by SEM, the product is dispersed nanometer zeolite. via N 2 Physical adsorption characterization, its BET external area is 70m 2 / g, and the product filtration rate is 10 times that of Comparative Example 1.

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PUM

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Abstract

The invention relates to a preparation method for high-dispersion zeolite molecular sieves. The preparation method includes preparing gel and performing hydrothermal crystallization on nanometer molecular sieves, pressing organochlorosilane in a crystallization kettle filled with crystallized matter through pressurization of nitrogen under the condition of stirring when the crystallization of the molecular sieves is finished so as to enable the organochlorosilane to fully contact and react with the surfaces of the molecular sieves, and collecting products after reaction of the organochlorosilane and the crystallized matter is finished. The mass ratio of the added organochlorosilane R is R/SIO2=0.01-2, the reaction time is no more than 100 hours, and the reaction temperature ranges from room temperature to 200 DEG C. The organochlorosilane is added when the crystallization of the molecular sieves is finished, and the condensation reaction of the organochlorosilane and the surface hydroxyl groups of the molecular sieves is utilized to block agglomeration among the molecular sieves, so that the defect that prior methods affect crystallization kinetics of the molecular sieves is overcome. Obtained molecular sieve products have good dispersibility and large specific surface areas, and are easy to filter.

Description

technical field [0001] The invention belongs to the field of preparation of zeolite molecular sieves, and relates to a method favorable for preparing highly dispersed small crystal grain zeolite molecular sieves. Background technique [0002] Zeolite molecular sieve is the most important component of inorganic microporous materials. It is a crystal material that can sieve substances at the molecular level. Its skeleton is composed of TO 4 A multi-dimensional four-connected structure formed by sharing vertices between tetrahedra, where T refers to Si, Al or other heteroatoms. Zeolite molecular sieves are widely used in industrial processes and high-tech materials due to their regular pore structure, unique ion exchange properties, shape-selective adsorption properties, easy modulation of composition and properties, high activity and selectivity of many small molecule catalytic reactions, etc. It is widely used in the field, especially the research fields of catalysis, adsorp...

Claims

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Application Information

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IPC IPC(8): C01B39/02
Inventor 郭洪臣刘春燕钱吉郑步梅李海龙
Owner DALIAN UNIV OF TECH
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