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Method for preparing hierarchical porous MCM-22 molecular sieves

A technology of MCM-22 and molecular sieve, which is applied in the field of catalytic chemistry, can solve the problems of reducing the mass transfer resistance of microporous molecular sieves, and has not yet seen research reports on MCM-22 molecular sieves, so as to improve mass transfer performance, expand the application range, and increase the effect of ability

Inactive Publication Date: 2012-12-05
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Introducing mesopores (with a pore size of 2-50nm) into molecular sieve crystals is an effective method that can significantly reduce the mass transfer resistance of microporous molecular sieves. However, there has been no research on the preparation of MCM-22 molecular sieves with intracrystalline mesoporous pores. to report

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  • Method for preparing hierarchical porous MCM-22 molecular sieves
  • Method for preparing hierarchical porous MCM-22 molecular sieves
  • Method for preparing hierarchical porous MCM-22 molecular sieves

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Experimental program
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Embodiment 1

[0015] The preparation of embodiment 1 hierarchical porous MCM-22 molecular sieve

[0016] (1) Preparation of MCM-22 precursor

[0017] Solid silica gel (dry basis 92%), NaAlO 2 Solution (16.8%Al 2 o 3 , 24.2%Na 2 O and 59.0%H 2 O), hexamethyleneimine (HMI), NaOH and deionized water are added to the reaction kettle in a certain order, and stirred at room temperature to obtain a mixture M, wherein the molar ratio of each component in M ​​is SiO 2 / Al 2 o 3 =32, Na 2 O / SiO 2 =0.1,H 2 O / SiO 2 =45; then the reactor was sealed, and dynamically crystallized at 170°C for 48 hours; after the reactor was cooled, the crystallized product was centrifuged, and the solid sample was washed and dried to obtain the MCM-22 molecular sieve precursor. Its SiO 2 / Al 2 o 3 The molar ratio was 27.

[0018] (2) Preparation of hierarchically porous MCM-22 molecular sieves

[0019] Add 2.19g of hexadecyltrimethylammonium bromide and 0.24g of NaOH into 60mL of deionized water, heat at 4...

Embodiment 2

[0022] The preparation of embodiment 2 hierarchical porous MCM-22 molecular sieves

[0023] Add 2.19g of cetyltrimethylammonium bromide and 0.48g of NaOH into 60mL of deionized water, heat at 50°C, and stir continuously to dissolve it to form solution S1; then add 0.2g of the MCM- 22 Add the precursor to S1, and keep stirring at 60°C for 120 minutes to obtain a suspension S2; after S2 is cooled to room temperature, adjust the pH value to 6 with dilute hydrochloric acid, and stir at room temperature for 45 minutes to obtain S3; S3 is centrifuged, and the resulting solid is dried at 30°C and roasted at 550°C to obtain the product. According to X-ray diffraction and nitrogen adsorption analysis, the obtained product is a multi-level porous MCM-22 molecular sieve.

Embodiment 3

[0024] The preparation of embodiment 3 hierarchical porous MCM-22 molecular sieves

[0025] Add 2.19g of cetyltrimethylammonium bromide and 0.96g of NaOH into 60mL of deionized water, heat at 40°C, and stir continuously to dissolve it to form solution S1; then add 0.5g of the MCM- 22 Add the precursor to S1, and keep stirring at 40°C for 200 minutes to obtain a suspension S2; after cooling S2 to room temperature, adjust the pH value to 7 with acetic acid, and stir at room temperature for 60 minutes to obtain S3; for S3 Carry out centrifugation, gained solid obtains product after 40 DEG C of drying and 550 DEG C of roasting. According to X-ray diffraction and nitrogen adsorption analysis, the obtained product is a multi-level porous MCM-22 molecular sieve.

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Abstract

The invention discloses a method for preparing hierarchical porous MCM-22 molecular sieves, which comprises the following specific steps of respectively adding cation surfactant and inorganic alkali into de-ionized water, heating mixture at 40-80 DEG C to be dissolved so as to obtain a solution S1; then, adding MCM-22 precursor into S1, and stirring for 60-200 min at 40-80 degrees centigrade to obtain suspension liquid S2; cooling S2 to room temperature, adjusting the pH value to 4-8 with acid, and continuously stirring for 30-60 min to obtain S3; and centrifugally separating S3, and drying and roasting the obtained solids to obtain the hierarchical porous MCM-22 molecular sieves. The hierarchical porous MCM-22 molecular sieves obtained by the method have transgranular meso pores and the external surface area of the hierarchical porous MCM-22 molecular sieves is remarkably more than that of the conventional MCM-22 molecular sieves, thereby being in favour of improving the mass transfer performance and the catalytic performance of the MCM-22 molecular sieves.

Description

technical field [0001] The invention belongs to the technical field of catalytic chemistry, and in particular relates to a preparation method of a multi-level porous MCM-22 molecular sieve. Background technique [0002] MCM-22 molecular sieve is a typical layered molecular sieve with MWW configuration. The skeleton contains two kinds of disconnected pore systems, one is the sinusoidal ten-membered ring channel in the layer, and the other is the interlayer. Twelve-membered ring supercage systems with ten-membered ring windows. Based on the unique pore structure, MCM-22 molecular sieve can be widely used in reaction processes such as alkylation, transalkylation and acylation. Like other types of microporous molecular sieves, the pore size of MCM-22 molecular sieve belongs to the micropore range (<2nm), which limits its application in catalytic conversion of larger molecules to a certain extent. [0003] A variety of post-treatment methods have been developed to improve th...

Claims

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Application Information

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IPC IPC(8): C01B39/02
Inventor 徐龙伢高宁宁谢素娟刘盛林李秀杰
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI