Method for synthesizing kilogram-stage nano molecular screen MCM-56 and template agent removing method

A nano-molecular sieve, MCM-56 technology, applied in the field of catalytic chemistry, can solve the problems of unsatisfactory demand, single material source, and reduced specific surface area, and achieve the effects of improving raw material utilization, shortening crystallization time, and mild reaction conditions

Inactive Publication Date: 2008-04-23
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Difficult to provide a very stable, single source of material for further research
In particular, the small-volume synthesis in the laboratory can no longer meet the demand for catalytic research of more than 100g
[0015] 2. Calcining the template removal agent at high temperature will easily cause the thin layer structure of MCM-56 to be distorted, the specific surface area will be reduced, and the area of ​​the active center that can be contacted will be reduced.
MCM-56 is a layered molecular sieve. Its crystal is mainly composed of single-layer unit cells and two-layer unit cells. The molecular sieve structure is distorted and the unit cell is curled, which reduces the contactable area of ​​the reaction and reduces the reactivity of the molecular sieve

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 543 grams of sodium aluminate (Al 2 o 3 44.7wt%, Na 2 O 39.2wt%) was dissolved in 5.3L water, and 1.9L organic template agent hexamethyleneimine (HMI) was added under vigorous stirring condition, and then silica sol (SiO 2 25wt%, Na 2 O 0.2wt%) 12.5L. The material ratio of reactants is in molar ratio:

[0039] SiO 2 / Al 2 o 3 =25

[0040] Oh- / SiO 2 =0.13

[0041] HMI / SiO 2 =0.29

[0042] h 2 O / SiO 2 =15

[0043] After stirring vigorously for 2 hours, it was loaded into a 30L stainless steel reaction kettle. The rotation speed of the reaction tank is 20-23 revolutions per minute, and the crystallization is carried out at 140° C. for 50 hours. After taking out, it is filtered, washed and dried. The obtained crystals were determined to be MCM-56 by X-ray diffractometer. SiO was obtained by chemical analysis 2 / Al 2 o 3 The molar ratio was 18.3. Transmission electron microscopy showed that MCM-56 flocculently aggregated into agglomerates, crystal pro...

Embodiment 2

[0045] Embodiment 1 gained sample and 30% hydrogen peroxide (H 2 o 2 ) solution (20mL / g), stirred at 95°C until no bubbles were generated, filtered with suction, and repeated the above process once. The dried MCM-56 is measured by X-ray diffractometer, thermogravimetric and infrared, and the obtained crystal is MCM-56 without template. Total specific surface area 700m 2 / g, total pore volume 1.71m 3 / g, micropore volume 0.26m 3 / g.

Embodiment 3

[0047] 695 grams of sodium aluminate (Al 2 o 3 44.7wt%, Na 2 O 39.2wt%) was dissolved in 2.7L of water, and 1.1L of hexamethyleneimine (HMI) was added under vigorous stirring, and then gradually dropped into silica sol (SiO 2 25wt%, Na 2 O 0.2wt%) 16L. The material ratio (molar ratio) of reactant is:

[0048] SiO 2 / Al 2 o 3 =25

[0049] Oh - / SiO 2 =0.13

[0050] HMI / SiO 2 =0.13

[0051] h 2 O / SiO 2 =10

[0052] After the raw materials were vigorously stirred for 2 hours, they were put into a 30L stainless steel reaction kettle. The rolling speed of the reaction tank is 20-23 rpm, and the crystallization is carried out at 150°C for 48 hours. Cool to room temperature, take out, filter and dry to obtain MCM-56. The obtained crystals were determined to be MCM-56 by X-ray diffractometer. SiO was obtained by chemical analysis 2 / Al 2 o 3 The molar ratio was 20.4. Transmission electron microscopy showed that MCM-56 flocculently aggregated into agglomerates,...

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Abstract

This invention discloses a method for synthesizing kilogram grade nanometer molecular sieve MCM-56, and method for removing metrix agent. The procedures are: mixing silicon source, aluminium source, alkali, metrix agent and water in proper ratio, heating at 80-200deg.C, crystallizing for 5-240hrs; taking the product out and proceeding water-washing, drying to obtain the inventive product MCM-56 molecular sieve. Said crystallization is in a 30L reaction tank and being rotating round a central horizontal axis at speed of 5-40 rpm. Hydrogen peroxide is used for removing metrix agent. In this invention, due to the use of less water and metrix agent to form athick raw material mud, it is beneficial to formation of molecular sieve kernels in great amount. The even heating in the reaction tank makes the final product being of crystalline phase homogeneous. No use of high temperature calcinations makes the skeleton keep its original structure. This inventive method is suitable for commercial production.

Description

technical field [0001] The invention belongs to the technical field of catalytic chemistry, and in particular relates to a kilogram-level large-scale dynamic synthesis method of nanometer-level MCM-56 molecular sieves and a method for removing templates. Background technique [0002] In 1994, Fung et al. reported a new type of layered catalytic material, MCM-56 molecular sieve, whose pore structure mainly includes a sinusoidal network channel system in the layer and twelve-membered ring holes on the outer surface. MCM-56 molecular sieve has a large molecular adsorption capacity, and the adsorption capacity of 1,3,5-trimethylbenzene after calcination reaches 35μL / g, which is at least 4 times that of MCM-22 and MCM-49. MCM-56 is a molecular sieve with MWW structure, mainly composed of single-layer unit cell crystals (~45%) and two-layer unit cell crystals (~55%). The crystal structure is extremely thin, with a large external specific surface area, and a large number of twelve ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04
Inventor 阚秋斌邢海军吴通好许宇贾明君张文祥吴淑杰王振旅
Owner JILIN UNIV
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