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Preparation and application of porous ZSM-5 zeolite molecular sieve aggregate

A ZSM-5, multi-level pore technology, applied in chemical catalytic materials and chemical application fields, can solve the problems of affecting the conversion rate of chemical synthesis and low time consumption, restriction of reaction molecular diffusion, large amount of template agent, etc., to achieve industrial promotion and application Promising, high conversion and selectivity, effects of a process that reduces secondary roasting

Inactive Publication Date: 2015-05-27
EAST CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The ZSM-5 zeolite molecular sieves prepared in the prior art have only micropores and no secondary pores. When used in macromolecular catalytic reactions, ZSM-5 zeolite is limited by the micropores, so that the diffusion of reaction molecules in the channels is greatly restricted. Limitation, which affects the conversion rate and low time consumption of chemical synthesis, and the synthesis process is cumbersome, requiring the addition of a secondary template agent, which requires a large amount of template agent and high preparation costs

Method used

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  • Preparation and application of porous ZSM-5 zeolite molecular sieve aggregate
  • Preparation and application of porous ZSM-5 zeolite molecular sieve aggregate
  • Preparation and application of porous ZSM-5 zeolite molecular sieve aggregate

Examples

Experimental program
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Effect test

Embodiment 1

[0021] a. Preparation of silica-alumina sol-gel

[0022] will contain 0.033mol Al 2 o 3 A solution of aluminum sulfate was added dropwise to a solution containing 1mol SiO 2 In the sodium silicate solution, add hydrochloric acid to adjust the pH value to 7 under stirring, filter after stirring for 30 minutes, and transfer the filter cake to the autoclave to replenish water to H 2 O / SiO 2 With a molar ratio of 25, polyhydroxylated silica-alumina sol-gels were prepared.

[0023] b. Preparation of seed directing agent

[0024] tetrapropylammonium hydroxide (TPAOH) with tetraethyl orthosilicate (TEOS) and H 2 O was mixed at a molar ratio of 0.35:1:20, stirred into a clear solution, and crystallized at 100°C for 24 hours to obtain a tetrapropylammonium seed directing agent.

[0025] c. Preparation of H-zeolite aggregates

[0026] Add the above-prepared tetrapropylammonium seed directing agent to the polyhydroxylated silicon-aluminum sol-gel at a molar ratio of 0.015 to the S...

Embodiment 2

[0031] Take 0.15 g of the hierarchically porous H-ZSM-5 zeolite molecular sieve aggregate prepared in Example 1 as a catalyst and add it to 7 g of cyclohexane with 0.7 g of tert-butanol and 0.5 g of phenol in a three-necked flask equipped with a reflux condenser, The hydroxylation reaction was carried out at 100 °C for 4 hours. After the reaction, the catalyst was filtered out by centrifugation. The conversion rate of phenol of the product was determined by gas chromatography to be 33%, and the selectivity was 98%.

Embodiment 3

[0033] a. Preparation of silica-alumina sol-gel

[0034] will contain 0.017mol Al 2 o 3 A solution of aluminum sulfate was added dropwise to a solution containing 1mol SiO 2 Add hydrochloric acid to adjust the pH value to 8 under stirring, filter after stirring for 30 minutes, and transfer the filter cake to the autoclave to replenish water to H 2 O / SiO 2 With a molar ratio of 25, polyhydroxylated silica-alumina sol-gels were prepared.

[0035] b. Preparation of seed directing agent

[0036] tetrapropylammonium bromide (TPABr) with tetraethyl orthosilicate (TEOS) and H 2 O was mixed at a molar ratio of 0.2:1:20, stirred into a clear solution, and crystallized at 100°C for 24 hours to obtain a tetrapropylammonium seed directing agent.

[0037] c. Preparation of H-zeolite aggregates

[0038] Add the above-prepared tetrapropylammonium seed directing agent to the polyhydroxylated silicon-aluminum sol-gel at a molar ratio of 0.015 to the Si of the synthesis system, stir and ...

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Abstract

The invention discloses a preparation and an application of a porous ZSM-5 zeolite molecular sieve aggregate. The preparation is characterized in that by adopting silicon-aluminum sol-gel, which is synthesized by an inorganic aluminum source and an organic silicon source, and added with seed crystal prepared by tetra propyl ammonium, as a guiding agent, the porous ZSM-5 zeolite molecular sieve aggregate with an open pore duct is synthesized through one-step process. The aggregate is taken as a catalyst for hydroxylation reaction of cyclohexane, tertiary butanol and phenol. Compared with the prior art, the aggregate structure, which is formed by stacking nano particles with particle size of 20-150 nm, has a specific surface area up to 600 m<2> / g, total pore volume up to 0.8cm<3> / g, and high conversation rate and selectivity, keeps the activities of monodisperse nano particles, effectively solves the problem that the nano particle catalyst is difficult to separate and short in service life in phenol hydroxylation reaction, and has a certain industrial popularization and application prospect and a remarkable economic value.

Description

technical field [0001] The invention relates to the technical field of chemical catalytic materials and chemical applications, in particular to the preparation and application of a multi-stage porous ZSM-5 zeolite molecular sieve aggregate with open channels. Background technique [0002] Microporous ZSM-5 crystals have uniform micropores, high specific surface area, flexible skeleton structure, and rich and controllable chemical composition, making them widely concerned in the field of separation and purification. At present, the common preparation methods of hierarchical porous ZSM-5 molecular sieves include: post-treatment method, soft template method, hard template method, etc. For example, mesopores are introduced through water vapor treatment, acid / alkali and other post-treatment methods; patent CN102689911 A discloses a method for preparing hierarchically porous ZSM-5 molecular sieve nanospheres with adjustable apertures by microwave alkali treatment; Jacobsen et al. ...

Claims

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Application Information

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IPC IPC(8): C01B39/40B01J29/40C07C37/11C07C39/06
CPCC01B39/40B01J29/40B01J2229/14B01J2523/31B01J2523/41C01P2002/72C01P2004/03C01P2004/04C01P2004/62C01P2004/64C01P2006/12C01P2006/14C01P2006/90C07C37/11C07C39/06
Inventor 陈丽吴海虹何鸣元
Owner EAST CHINA NORMAL UNIVERSITY
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