Molecular sieve pore-expanding method

A treatment method and molecular sieve technology, applied in molecular sieves and alkali exchange compounds, chemical instruments and methods, inorganic chemistry, etc., can solve problems such as unfavorable catalytic activity, and achieve the effect of increasing the size of micropores and increasing the volume of micropores

Active Publication Date: 2020-06-23
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, defects in molecular sieves are generally considered to be detrimental to the structures that enhance their catalytic activity.

Method used

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  • Molecular sieve pore-expanding method
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  • Molecular sieve pore-expanding method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Put 63g of oxalic acid dihydrate into 750g of water, and after preparing a solution, disperse 5g of the initial ammonium-type mordenite molecular sieve (MOR-P) in it, treat it at 90°C for 46h, and then filter it. After drying for 12 hours, the obtained sample was designated as MOR-A.

[0024] Disperse 10 g of the obtained acid-treated sample MOR-A in 300 g of a 30% ammonium fluoride solution, heat the above mixture to 50 ° C, and treat it under ultrasonic conditions for 1 h, then filter, wash and dry the mixture, and the obtained sample is recorded as Make MOR-A-AF. The micropore volume of the final product molecular sieve is changed from 0.154cm 3 / g increased to 0.163cm 3 / g, and a certain amount of secondary pores with a size slightly larger than the intrinsic microporous structure are produced.

Embodiment 2

[0026] Disperse 50 g of Y-type molecular sieve molecular sieves in 500 g of water, and add 50 g of ammonium sulfate thereinto, and stir to make them evenly mixed. Heat the above-mentioned molecular sieve slurry to 85°C, and add sulfuric acid with a concentration of 2 mol / l dropwise to it until the pH value of the system reaches 1.8. After maintaining for 30 minutes, filter the above-mentioned mixture, wash the filter cake fully and dry it. The obtained sample is recorded as USY -A.

[0027] 10 g of the sample (Y-A) obtained by the above acid treatment was dispersed in 100 g of ammonium fluoride solutions with mass fractions of 10% and 20%, respectively, and treated for 10 min at 0°C in the presence of ultrasound. Then filter, wash the filter cake well, and dry at 100°C for 12h. The resulting samples were designated Y-A-AF1, Y-A-AF2 and Y-A-AF3, respectively.

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Abstract

A molecular sieve pore-expanding method comprises the following steps: (1) introducing defects into a molecular sieve: preprocessing the molecular sieve by using an acid solution, an alkali solution or water vapor, cleaning, and drying the preprocessed molecular sieve to obtain a defect-containing molecular sieve; and (2) removing skeleton atoms in the defect-containing molecular sieve obtained inthe step (1) by adopting an ammonium fluoride solution to realize regulation and control of a pore structure. The method will not obviously destroy the crystal structure of the molecular sieve, the micro-pore size of the obtained molecular sieve is properly increased, the micro-pore volume is increased, and the molecular sieve has a micro-pore mesopore stepped pore structure after being treated.

Description

technical field [0001] The invention relates to a post-treatment method for molecular sieves, that is, a new method for regulating the pore structure of molecular sieves, improving the mass transfer capacity of molecular sieves and increasing the accessibility of active sites. Background technique [0002] Molecular sieve is an important crystalline porous material of aluminosilicate, and its pore structure and acidity are two important properties. The pore structure endows the molecular sieve with excellent shape selectivity, and the acidic sites provide the molecular sieve with reactivity. Therefore, molecular sieves have been widely used in the field of heterogeneous catalysis. However, during the catalytic conversion reaction of macromolecular substances, the narrow micropore structure of molecular sieves limits the diffusion of macromolecules in their crystals. [0003] In order to enhance the mass transfer and diffusion ability of the molecular sieve, some atoms in t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/26C01B39/24C01B39/02
CPCC01B39/26C01B39/24C01B39/026C01P2002/72C01P2006/14Y02P20/52
Inventor 覃正兴沈焰丰许明睿王晔刘欣梅王纯正白鹏郭海玲
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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