Beta molecular sieve with adjustable relative content of polymorphs and synthetic method thereof

A technology of relative content and synthesis method, applied in the field of Beta zeolite molecular sieve preparation

Active Publication Date: 2016-07-13
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, so far, although there have been studies to synthesize pure polymorph C and enriched polymorphs A and B by using specific templates or reaction conditions, there is no free adjustment of the three polymorphs in Beta molecular sieves within a certain range. content reports

Method used

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  • Beta molecular sieve with adjustable relative content of polymorphs and synthetic method thereof
  • Beta molecular sieve with adjustable relative content of polymorphs and synthetic method thereof
  • Beta molecular sieve with adjustable relative content of polymorphs and synthetic method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0050] Beta molecular sieves with adjustable relative content of polymorphs were synthesized under the condition that the molar ratio of fluorine source to silicon source was 0.2:1.

[0051] Add 7.27g of N-isobutyl-N-methylpyrrole hydroxide aqueous solution with a mass fraction of 43.73% into the beaker, then add 15g of deionized water and 8.33g of tetraethyl silicate, and stir at room temperature for 3 Hours, then continue stirring in a constant temperature water bath at 60°C to promote the hydrolysis of tetraethyl silicate until the molar ratio of water to silicon source reaches 4:1 to form a gel, and at this time, add hydrogen with a mass fraction of 40% to the gel drop by drop 0.50g of hydrofluoric acid, stirred evenly, transferred to a 30ml polytetrafluoroethylene-lined stainless steel hydrothermal kettle and crystallized in an oven at 175°C for 7 days. After the crystallization was completed, the product was taken out and washed with deionized water until neutral. Transf...

Embodiment 2

[0054] Beta molecular sieves with adjustable relative content of polymorphs were synthesized under the condition that the molar ratio of fluorine source to silicon source was 0.3:1:

[0055] Add 7.27g of N-isobutyl-N-methylpyrrole hydroxide aqueous solution with a mass fraction of 43.73% into the beaker, then add 15g of deionized water and 8.33g of tetraethyl silicate, and stir at room temperature for 3 Hours, then continue stirring in a constant temperature water bath at 60°C to promote the hydrolysis of tetraethyl silicate until the molar ratio of water to silicon source reaches 4:1 to form a gel, and at this time, add hydrogen with a mass fraction of 40% to the gel drop by drop 0.75g of hydrofluoric acid, stirred evenly, transferred to a 30ml polytetrafluoroethylene-lined stainless steel hydrothermal kettle and crystallized in an oven at 175°C for 7 days. After the crystallization was completed, the product was taken out and washed with deionized water until neutral. Transf...

Embodiment 3

[0058] Beta molecular sieves with adjustable relative content of polymorphs were synthesized under the condition that the molar ratio of fluorine source to silicon source was 0.4:1:

[0059] Add 7.27g of N-isobutyl-N-methylpyrrole hydroxide aqueous solution with a mass fraction of 43.73% into the beaker, then add 15g of deionized water and 8.33g of tetraethyl silicate, and stir at room temperature for 3 Hours, then continue stirring in a constant temperature water bath at 60°C to promote the hydrolysis of tetraethyl silicate until the molar ratio of water to silicon source reaches 4:1 to form a gel, and at this time, add hydrogen with a mass fraction of 40% to the gel drop by drop 1.00g of hydrofluoric acid, stirred evenly, transferred to a 30ml polytetrafluoroethylene-lined stainless steel hydrothermal kettle and crystallized in an oven at 175°C for 7 days. After the crystallization was completed, the product was taken out and washed with deionized water until neutral. Transf...

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Abstract

The invention relates to a Beta molecular sieve with adjustable relative content of polymorphs and a preparation method thereof. In comparison with a traditional Beta molecular sieve, the Beta molecular sieve of the invention is characterized in that relative content of three polymorphs A, B and C is adjustable. The invention specifically relates to a pure silicon or transition metal (such as titanium, zirconium, etc) heteroatom-doped Beta molecular sieve synthesized under specific reaction conditions by the use of an organic template. The template of the invention is N-isobutyl-N-methylpyrrolidine hydroxide; a fluorine source is hydrofluoric acid; a silicon source is tetraethyl orthosilicate; a titanium source is tetraethyl titanate or tetrabutyl titanate; and a zirconium source is zirconium n-butoxide. By modulating the ratio of fluorine to template in the synthetic system, relative content of the three polymorphs A, B and C can be modulated.

Description

technical field [0001] The invention belongs to the technical field of preparation of Beta zeolite molecular sieves, and specifically designs and uses an organic template agent to synthesize Beta molecular sieves doped with pure silicon and transition metal heteroatoms such as titanium and zirconium under specific conditions. Compared with the traditional Beta molecular sieve, the Beta molecular sieve has the characteristics of adjustable relative contents of three polymorphs A, B and C. technical background [0002] Natural Beta zeolite exists in nature (tschernichite), and the work of artificially synthesizing Beta molecular sieves was first realized in an alkaline system by Mobil Company in 1967. Beta molecular sieve is a molecular sieve crystal with a three-dimensional 12-membered ring channel. Beta molecular sieve has excellent performance in reactions such as hydrocarbon cracking, alkane aromatization, olefin epoxidation, sugar isomerization and epimerization. reactiv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04
Inventor 田志坚章冠群王炳春马怀军徐仁顺徐竹生
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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