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

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 ...

Examples

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,...

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 ...

Examples

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,...