Preparation method of cascade pore molecular sieve

A molecular sieve and stepped pore technology, which is applied in the directions of crystalline aluminosilicate zeolite, octahedral crystalline aluminosilicate zeolite, etc., can solve the problems such as the restriction of the improvement degree of molecular sieve diffusion capacity, and achieve the improvement of adsorption and diffusion capacity and wide applicability. , the effect of improving mass transfer capacity

Active Publication Date: 2021-07-23
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This phenomenon greatly restricts the degree of improvement of the diffusion capacity of molecular sieves through post-treatment methods.

Method used

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  • Preparation method of cascade pore molecular sieve
  • Preparation method of cascade pore molecular sieve
  • Preparation method of cascade pore molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A kind of preparation method of step hole MFI molecular sieve, its preparation method comprises the steps:

[0037] Synthetic raw material MFI molecular sieve: disperse 2.5g sodium hydroxide and 20.3g tetrapropylammonium hydroxide in 450g deionized water, stir at room temperature for 1h to fully dissolve and mix evenly; then add 3.75g aluminum nitrate nonahydrate to the solution , 52g tetraethyl orthosilicate, stirred at room temperature for 24 hours; after it was fully hydrolyzed and mixed uniformly, the molecular sieve precursor was transferred to a crystallization kettle with Teflon lining, placed in an oven, and heated at 170°C for 10 hours; then The sample was taken out, separated by filtration, fully washed with deionized water, and dried at 100°C for 12 hours to obtain the raw material MFI molecular sieve MFI-1 with a relative crystallinity of 76%;

[0038]Preparation of step-pore MFI molecular sieve: Disperse the MFI-1 molecular sieve obtained in step 1) in 0.3 ...

Embodiment 2

[0040] A kind of preparation method of step hole MFI molecular sieve, its preparation method comprises the steps:

[0041] Synthetic raw material MFI molecular sieve: disperse 2.5g sodium hydroxide in 150g deionized water, stir at room temperature for 1 hour to fully dissolve and mix evenly; then add 3.75g aluminum nitrate nonahydrate and 52g tetraethyl orthosilicate to the solution, Stir at room temperature for 24 hours; after it is fully hydrolyzed and mixed evenly, add 50 mg of MFI molecular sieve seed crystals to it, stir for 30 minutes to make it evenly mixed, transfer the molecular sieve precursor to a Teflon-lined crystallization kettle, and place it in an oven. Heat at 170°C for 8 hours; then take out the sample, filter and separate the sample, wash it thoroughly with deionized water, and dry it at 100°C for 12 hours to obtain the raw material molecular sieve MFI-2 with a relative crystallinity of 78%;

[0042] Preparation of step-pore MFI molecular sieve: Disperse the...

Embodiment 3

[0044] A preparation method of step hole ultra-stable Y-type molecular sieve, the preparation method comprising the following steps:

[0045] Synthetic raw material Y type molecular sieve: get 20.60g sodium metaaluminate solution (21.0wt%Na 2 O, 3.20wt% Al 2 o 3 ) and 20.90g water glass (28.45wt% SiO 2 ,8.89wt%Na 2 O) Disperse it evenly in 8.60g deionized water, stir for 30min and wait for it to be fully mixed, then let it stand for aging for 16h; take 50g of the above mixture, 75.86g of water glass, and 16.88g of sodium metaaluminate evenly dispersed in 25g of deionized In water, add 51.05g aluminum sulfate solution (7.60wt% Al 2 o 3 ), continue stirring for 1 hour, place the obtained gel in a Teflon-lined crystallization kettle and heat it at 98°C for 10 hours; then take out the sample, filter and separate the sample, wash it thoroughly with deionized water, and dry it at 100°C for 12 hours , obtain raw material molecular sieve Y-1, its relative crystallinity is 72%; ...

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Abstract

The invention relates to a preparation method of a cascade pore molecular sieve, which comprises the following steps: (1) dispersing a silicon source, an aluminum source and / or a phosphorus source and a template agent in water, uniformly conducting stirring and mixing, placing the obtained mixture in a crystallization kettle, and conducting heating for 0.5-30 days in a drying oven at the heating temperature of 5-300 DEG C; (2) taking out a sample obtained in the step (1) from the oven, conducting filtering and separating, fully conducting washing with deionized water, and conducting drying; (3) roasting the dried sample obtained in the step (2), and removing the template agent in the molecular sieve while satisfying that the crystallinity of the obtained initial molecular sieve is 50-90% and the total crystallization sample is 100%; and (4) carrying out hydrothermal treatment or chemical treatment on the template agent removed sample obtained in the step (3) to finally obtain the cascade pore molecular sieve. According to the method, the compact and stable structure on the surface layer of the molecular sieve is dissolved while the pore channel structure of the molecular sieve is regulated and controlled, and the mass transfer diffusivity of the molecular sieve can be improved to a greater extent.

Description

technical field [0001] The invention belongs to the technical field of molecular sieve synthesis, and relates to a method for synthesizing and preparing step-pore molecular sieves. Background technique [0002] Molecular sieves are widely used in many fields such as adsorption, catalysis, and separation because of their large specific surface area, unique pore structure, and excellent adjustable acid properties. However, several types of molecular sieves widely used in industry, such as MFI, FAU, MOR, and BEA, are all microporous materials. Due to the narrow micropore openings, their weak mass transfer and diffusion capabilities limit their catalytic performance. To this end, researchers have taken a series of measures aimed at adjusting the pore structure of molecular sieves and improving their mass transfer and diffusion capabilities. The methods adopted can be mainly divided into the following categories. By synthesizing nanometer-sized molecular sieve catalysts, the dif...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04C01B39/24
CPCC01B39/04C01B39/24C01P2004/03C01P2002/72Y02P20/52
Inventor 覃正兴沈焰丰王丽娟王博程铭王纯正吕玉超白鹏郭海玲刘欣梅
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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