Synthetic method of mesoporous-microporous composite ZSM-5/MCM-41 molecular sieve

A technology of MCM-41 and ZSM-5, applied in the field of synthesis of microporous-mesoporous composite ZSM-5/MCM-41 molecular sieve, can solve problems such as environmental pollution

Active Publication Date: 2012-05-23
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method requires the introduction of F in microporous synthesis - , there is a certain pollution to the environment

Method used

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  • Synthetic method of mesoporous-microporous composite ZSM-5/MCM-41 molecular sieve
  • Synthetic method of mesoporous-microporous composite ZSM-5/MCM-41 molecular sieve
  • Synthetic method of mesoporous-microporous composite ZSM-5/MCM-41 molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] (a) Alkaline treatment of ZSM-5 molecular sieve: 5g of ZSM-5 microporous molecular sieve (Si / Al molar ratio=27) was dissolved in 150ml of 0.2mol / L NaOH solution and stirred at 60°C for 5h. Then, it is filtered and dried to obtain ZSM-5 etched by alkali treatment.

[0031] (b) Heat 4.8g CTAB and dissolve it in 113ml distilled water, and let it stand for 8-10min after dissolving. Add 25g Na to the above solution 2 SiO 3 ·9H 2 O, stir and mix well, then add 1.584g of ZSM-5 that has been etched by alkali treatment, the molar composition of the system after stirring is: 1SiO 2 :0.15CTAB:65H 2 O, then use 2mol / L sulfuric acid to adjust pH=10.5, continue to stir at room temperature for 1h, then put it into the reaction kettle, and crystallize at 110°C for 24h. After the completion of crystallization, suction filtration, drying, and calcination at 550 ℃ for 6 hours to obtain the microporous-mesoporous ZSM-5 / MCM-41 composite molecular sieve sample ZM-1.

Embodiment 2

[0033] Heat 4.8g CTAB to dissolve it in 146ml distilled water, wait for 8min-10min after dissolving. Add 25g Na to the above solution 2 SiO 3 ·9H 2 O, after stirring and mixing well, add 0.768g of ZSM-5 which has been etched by alkali treatment in Example 1, and the molar composition of the system after stirring is 1SiO 2 :0.15CTAB:80H 2 O, then use 2mol / L sulfuric acid to adjust pH=10.5, continue to stir at room temperature for 2h, then put it into the reactor, and crystallize at 100℃ for 72h. After the completion of crystallization, suction filtration, drying, and calcination at 550°C for 6 hours to obtain the microporous-mesoporous ZSM-5 / MCM-41 composite molecular sieve sample ZM-2.

Embodiment 3

[0035] (a) Acid treatment of ZSM-5: 5g of ZSM-5 microporous molecular sieve (Si / Al molar ratio=27) was dissolved in 150ml of 0.1mol / L citric acid solution, and stirred at 80°C for 2h. Then filter and dry to obtain ZSM-5 etched by acid treatment.

[0036] (b) Heat 4.8g CTAB and dissolve it in 146mL distilled water, wait for 8min~10min after dissolution. Add 25g Na to the above solution 2 SiO 3 ·9H 2 O, stir and mix well, add 1.584g of ZSM-5 that has been acid treated and etched, and the molar composition of the system after stirring is 1SiO 2 :0.15CTAB:80H 2 O, then use 2mol / L sulfuric acid to adjust pH=10.5, continue to stir at room temperature for 3h, then put it into the reactor, and crystallize at 110℃ for 24h. After the completion of crystallization, suction filtration, drying, and calcination at 550°C for 6 hours to obtain the microporous-mesoporous ZSM-5 / MCM-41 composite molecular sieve sample ZM-3.

[0037] figure 1 It is the X-ray diffraction (XRD) spectrum of ZM-3, from w...

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Abstract

The invention relates to a synthetic method of a mesoporous-microporous composite ZSM-5/MCM-41 molecular sieve. The method comprises the steps of: adding a ZSM-5 microporous molecular sieve into acid or alkali solution, wherein the hydrogen ion concentration in the acid solution is 0.1 mol/L to 1.0 mol/L, the hydroxy radical concentration in the acid solution is 0.1 mol/L to 0.5 mol/L, and the mass ratio of liquid to solid is 30; dissolving CTAB (Cetyltrimethyl Ammonium Bromide) into water, adding a silicon source or the silicon source and an aluminum source to obtain clear solution, adding the ZSM-5 which is etched by acid or alkali, regulating pH value by sulfuric acid with the concentration of 2 mol/L, crystallizing, filtering, drying and roasting, wherein the mass ratio of ZSM-5 to CTAB is 0.08 to 0.39, and the molar ratio of SiO2 to CTAB to H2O in a synthetic gel system is 1 to 0.15 to (60-120). The method has the advantages of simple operation and good reproducibility.

Description

Technical field [0001] The invention relates to a method for synthesizing microporous-mesoporous composite ZSM-5 / MCM-41 molecular sieve. Background technique [0002] The research on the microporous-mesoporous composite molecular sieve first started with the one-step continuous synthesis process reported by Kloetstra to grow MCM-41 mesoporous molecular sieve on the surface of faujasite (FAU) (KRKloetstra et al. Microporous Material., 1996 , 6: 287~293). In this technology, FAU is exchanged with the surfactant cetyltrimethylammonium bromide (CTAB) in advance to obtain a surface rich in CTAB cations, and MCM-41 is grown by self-assembly of inorganic species to prepare FAU / MCM- 41 composite molecular sieve. This assembly method is limited to low-silicon type microporous molecular sieve, and the process is relatively complicated. [0003] Karlsson et al. used CTAB and tetradecyltrimethylammonium bromide as two templates, and after two-step crystallization, they successfully prepared...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04
Inventor 张志华阎子峰孙发民王东青宋春敏田然王有和赵野乔柯戴宝琴秦丽红王甫村张占全吕倩李海岩王莹莹马守涛洪梅
Owner PETROCHINA CO LTD
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