ZSM-5 molecular sieve with different acid distribution and preparation method thereof

A technology of ZSM-5 and molecular sieve, which is applied in the direction of crystalline aluminosilicate zeolite, borocarbane silicone crystalline aluminosilicate zeolite, etc., can solve the problems of limiting shape-selective performance and acid properties that are difficult to meet their needs, and achieve broad The effect of applying the foreground

Active Publication Date: 2015-07-22
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For some reaction processes that require superacids or reaction processes in which superacids are combined with strong acids and weak acids, the acid properties of ZSM-5 molecular sieves prepared by existing methods are difficult to meet their needs, which limits the application of their good shape-selective properties.

Method used

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  • ZSM-5 molecular sieve with different acid distribution and preparation method thereof
  • ZSM-5 molecular sieve with different acid distribution and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] In the first step, sodium hydroxide and aluminum sulfate are added to deionized water, tetrapropylammonium bromide is weighed and added to the solution, after stirring for 0.5 hours, silica sol is added, after stirring evenly, it is loaded into a stainless steel crystallization kettle, Constant temperature crystallization at 170°C for 48 hours, then cooled to room temperature;

[0019] In the second step, stir the cooled mixture after crystallization, and directly add white carbon black after stirring evenly (the addition amount is 63wt% of the first step, calculated as silicon dioxide), stir for 2 hours, and put it into a stainless steel crystallization kettle In 180°C constant temperature crystallization for 24 hours, then cooled to room temperature, washed, dried and calcined to obtain ZSM-5 molecular sieve. Synthetic raw material molar ratio: Al 2 o 3 :46SiO2 2 :15.6 TPA + :11.1Na 2 O:5407H 2 O.

Embodiment 2

[0023] In the first step, sodium hydroxide and aluminum sulfate are added to deionized water, tetrapropylammonium bromide is weighed and added to the solution, after stirring for 0.5 hours, silica sol is added, after stirring evenly, it is loaded into a stainless steel crystallization kettle, Constant temperature crystallization at 140°C for 48 hours, then cooled to room temperature;

[0024] In the second step, stir the cooled mixture after crystallization, and directly add silica sol after stirring evenly (the amount added is 91wt% of the first step, calculated as silicon dioxide), stir for 2 hours, and put it into a stainless steel crystallization kettle , constant temperature crystallization at 180°C for 18 hours, then cooled to room temperature, washed, dried, and calcined to obtain ZSM-5 molecular sieve. Synthetic raw material molar ratio: Al 2 o 3 :57SiO2 2 :20.8 TPA + :11.1Na 2 O:5604H 2 O.

Embodiment 3

[0026] In the first step, add sodium hydroxide and sodium aluminate to deionized water, weigh tetrapropylammonium bromide and add it to the solution, stir for 0.5 hours, add silica sol, stir evenly, and put it into a stainless steel crystallization kettle , constant temperature crystallization at 180°C for 12 hours, then cooled to room temperature;

[0027] In the second step, stir the cooled mixture after crystallization, add white carbon black after stirring evenly (the addition amount is 55wt% of the first step, calculated as silicon dioxide), stir for 2 hours, and put it into a stainless steel crystallization kettle , constant temperature crystallization at 180°C for 18 hours, then cooled to room temperature, washed, dried and calcined to obtain ZSM-5 molecular sieve. Synthetic raw material molar ratio: Al 2 o 3 :77SiO2 2 :15.6 TPA + :11.1Na 2 O:4700H 2 O.

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Abstract

The invention relates to a ZSM-5 molecular sieve with different acid distribution and a preparation method thereof. According to the molecular sieve, the molar ratio of silicon oxide to aluminium oxide is 40-100, the molecular sieve possesses weak acid acidity, strong acid acidity and superacid acidity at the same time, the total acid content is 0.3-0.82 mmol / g, the molar ratio of the acid content sum of strong acids and superacids to the acid content of weak acids is 1.1-2.2, and the molar ratio of Bronsted acids to Lewis acids is 1..1-1.9. The preparation method comprises: first step, performing crystallization on a mixture containing sodium hydroxide, a template, water, an aluminium source and a silicon source; and second step, adding a proper amount of a silicon source into the crystallization product of the first step, performing crystallization at a certain temperature, then washing ,drying and roasting to obtain ZSM-5 molecular sieve. The molecular sieve provides an excellent catalytic material for catalytic processes needing relatively more superacid amount or needing different acidity, and have wide application prospect in the catalytic fields such as alkylation, isomerization and the like.

Description

technical field [0001] The invention belongs to the field of molecular sieve synthesis, and in particular relates to a ZSM-5 molecular sieve with different acid distributions and a preparation method thereof. Background technique [0002] In 1984, after Haag et al first proposed that framework aluminum is the active center of silica-alumina zeolite molecular sieves, according to the properties of donating protons and accepting electrons, the concepts of Bronsted (ie B acid) and Lewis acid (ie L acid) were introduced to distinguish zeolite molecular sieves type of acid. by NH 3 -High-temperature peaks and low-temperature peaks in the TPD spectrum to represent strong acid sites and weak acid sites, thereby characterizing the acid strength distribution of silica-alumina molecular sieves. ZSM-5 molecular sieve has a unique three-dimensional channel structure and shape selection of acid strength distribution. It also has the characteristics of high silicon-aluminum ratio, lipop...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B39/40
Inventor 秦波张喜文孙潇磊刘全杰张志智
Owner CHINA PETROLEUM & CHEM CORP
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