Nano composite meso-microporous molecular sieve and preparation method thereof

A microporous molecular sieve and nanocomposite technology, applied in the direction of crystalline aluminosilicate zeolite, can solve the problem of difficult control of crystal grain size, and achieve the effects of energy saving, simple process and improved cracking activity

Inactive Publication Date: 2008-11-26
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for composite molecular sieves with micropore and mesopore double pore structure, due to the stepwise crystallization required for preparation, the grain size is not easy to control, and there is no report on the preparation method of nano-microporous and mesoporous composite molecular sieves.

Method used

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  • Nano composite meso-microporous molecular sieve and preparation method thereof
  • Nano composite meso-microporous molecular sieve and preparation method thereof
  • Nano composite meso-microporous molecular sieve and preparation method thereof

Examples

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Embodiment 1

[0018] Example 1: 120.00 g of tetraethylammonium hydroxide aqueous solution and 2.8 g of sodium carbonate were added to a polytetrafluoroethylene static reaction internal kettle, and 6.84 g of aluminum sulfate and 36.0 g of silica gel were added successively under stirring. Gradually raise the temperature at 0.1°C / min to 140°C for crystallization for 20 hours, and cool to room temperature to obtain emulsion A; electron microscopy shows that the nanoemulsion particles are about 25nm. Under the condition of water bath at 35°C, add 6.2g of cetyltrimethylammonium bromide (CTMAB) into 260.5g of water to dissolve, then add 0.84g of sodium aluminate and 51.5ml of A emulsion in turn, and slowly add 26.0g of ml (3-4 seconds / drop) of tetraethyl orthosilicate, adjust the pH value of the solution to about 10.50 with concentrated ammonia water, and dynamically crystallize at 35°C for 22 hours. The crystallized product is filtered, washed, and dried at 550 The templating agent is removed by...

Embodiment 2

[0019] Example 2: 85.71 g of tetraethylammonium hydroxide aqueous solution and 4.5 g of urea were added to a polytetrafluoroethylene static reaction internal kettle, and 4.80 g of sodium metaaluminate and 36.00 g of silica gel were sequentially added under stirring. Raise the temperature at a rate of 0.1°C / min to 120°C for crystallization for 30 hours, and cool to room temperature to obtain nanoemulsion A with a microporous structure, and the particle size is 22nm. Under the condition of water bath at 35°C, add 4.76g of cetyltrimethylammonium bromide (CTMAB) into 181.4g of water to dissolve, then add 0.92g of sodium aluminate and 154.6ml of A emulsion in turn, and slowly add 28.0ml of ml (3-4 seconds / drop) of water glass solution, adjust the pH value of the solution to 10.00 with concentrated ammonia water, and dynamically crystallize at 35°C for 22h. Medium calcination for 7 hours to remove the template agent to obtain a molecular sieve with mesoporous Beta / MCM-41 structure w...

Embodiment 3

[0020]Example 3: 171.43g of tetraethylammonium hydroxide aqueous solution and 2.64g of sodium acetate were added to a polytetrafluoroethylene static reaction internal kettle, and 4.84g of aluminum sulfate and 36.00g of silica gel were added successively under stirring. Raise the temperature at a rate of 0.1°C / min to 140°C for crystallization for 28 hours, and cool to room temperature to obtain a Beta molecular sieve emulsion A with a particle size of 30nm. Under the condition of water bath at 40°C, add 10.40g of cetyltrimethylammonium bromide (CTMAB) into 260.5g of water to dissolve, then add 0.50g of sodium aluminate and 51.5ml of A emulsion in turn, and slowly add 26.0g of ml (3-4 seconds / drop) of tetraethyl orthosilicate, adjust the pH value of the solution to 10.90 with concentrated ammonia water, and dynamically crystallize at 40°C for 22 hours. The templating agent was removed by calcining in the atmosphere for 7 hours, and a mesoporous Beta / MCM-41 molecular sieve with a...

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Abstract

The invention relates to a nano-composite molecular sieve and a preparing method thereof. Silica sol and sodium metaaluminate are taken as silicon source and aluminum source respectively, and step-by-step synthesis of crystallization is adopted by utilizing surfactant hexadecyl trimethyl ammonium bromide (CATB) and tetraethyl ammonium hydroxide (TEAOH) used for synthesizing a porous Beta molecular sieve as a template agent; in the first step of crystallization, an additive is added for controlling the solvent of the silicon source and the aluminum source to synthesize nano Beta latex; low-temperature dynamic crystallization is adopted in the second step; at the temperature of 30 to 40 DEG C, a composite molecular sieve is synthesized; finally a Beta/MCM-41nano-composite molecular sieve with grain size being 50 to 100 nanometers is produced after the processing steps of filtering, washing, drying and roasting.

Description

technical field [0001] The invention relates to a nano-composite mesoporous molecular sieve and a preparation method thereof, in particular to a nano-molecular sieve with a Beta / MCM-41 composite pore structure and a preparation method thereof. Background technique [0002] Microporous molecular sieve has a uniform and well-developed microporous structure and strong acidity, but its practical application is limited due to its limited pore size, which restricts larger molecules from entering its pore cavity, or the macromolecules formed in its pore cavity cannot escape quickly. scope. In 1992, Mobil Corporation synthesized the M41S series molecular sieves with uniform and regular pore structure, large specific surface area, and adjustable pore diameter within the range of 2-10nm. However, due to its long-range ordered structure, the pore wall is completely amorphous. The state presents weak acidity and hydrothermal stability, so its industrial application range is greatly res...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04
Inventor 李建伟卞金辉李英霞陈标华
Owner BEIJING UNIV OF CHEM TECH
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