Method for preparing MCM-36 molecular sieve under mild conditions

A technology of MCM-36 and MCM-22, which is applied in the field of preparing MCM-36 molecular sieves, can solve the problems of destroying structural integrity and reducing the acidity of molecular sieves

Active Publication Date: 2021-02-26
陕西双翼煤化科技实业集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high solubility of silica in highly alkaline aqueous solution during the pillaring process, it will still destroy the structural integrity and reduce the acidity of molecular sieves.

Method used

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  • Method for preparing MCM-36 molecular sieve under mild conditions
  • Method for preparing MCM-36 molecular sieve under mild conditions
  • Method for preparing MCM-36 molecular sieve under mild conditions

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1. Preparation of layered MCM-22(P)

[0026] According to the molar ratio: SiO 2 / Al 2 O 3 =50, OH – / SiO 2 =0.14, HMI / SiO 2 =0.35, H 2 O / SiO 2 =45, at room temperature, dissolve 0.36g NaOH in 50.32g deionized water, and then continue to add 0.30g NaAlO under stirring 2 , 9.34g SiO was added dropwise after it was completely dissolved 2 The sol continued to be stirred for 30mins, and then 2.18g HMI was added dropwise. The resulting mixed solution was moved into a stainless steel reactor with a 100mL polytetrafluoroethylene lining, installed in a homogeneous reactor, and stirred for 7 days at 60r / min at 150°C. . After the reaction was completed, the stainless steel reactor was removed from the homogeneous reactor and cooled in flowing cold water, separated by a centrifuge, washed with deionized water for several times to about pH=7, and dried in a drying oven at 60°C for 12 hours to obtain Layered MCM-22.

[0027] 2. Intercalation swelling of MCM-22(P)

[0028...

Embodiment 2

[0035] 1. Preparation of layered MCM-22(P)

[0036] This step is the same as step 1 of Example 1.

[0037] 2. Intercalation swelling of MCM-22(P)

[0038] According to the mass ratio: H 2 O / MCM-22(P)=40, TPAOH / MCM-22(P)=10, Gemini / MCM-22(P)=8, grind 1 g of layered MCM-22(P) into powder, 20 g Deionized water was added to a 150mL flask with magnetic stirring; 10g TPAOH, 20g H 2 O and 8g Gemini quaternary ammonium salt cationic surfactant were added to the beaker, poured into the aforementioned flask after sonication for 30mins and stirred for 5mins, and the pH value of the mixed solution in the flask was controlled between 8 and 9 by adding TPAOH, at 35°C The mixture was stirred in an oil bath for 16 h, washed with ethanol and deionized water by centrifugation, and finally dried in a drying oven at 35°C to obtain swollen MCM-22(P).

[0039] The structural formula of the Gemini quaternary ammonium salt cationic surfactant of the present embodiment is as follows:

[0040] ...

Embodiment 3

[0044] 1. Preparation of layered MCM-22(P)

[0045] This step is the same as step 1 of Example 1.

[0046] 2. Intercalation swelling of MCM-22(P)

[0047] According to the mass ratio: H 2 O / MCM-22(P)=45, TPAOH / MCM-22(P)=20, Gemini / MCM-22(P)=12, 1g of layered MCM-22(P), 25g ground into powder Deionized water was added to a 150mL flask with magnetic stirring; 20g TPAOH, 20g H 2 O and 12g Gemini quaternary ammonium salt cationic surfactant were added to the beaker, poured into the aforementioned flask after sonicating for 30mins and stirred for 5mins, and the pH value of the mixture in the flask was controlled between 8 and 9 by adding TPAOH, at 35°C The mixture was stirred in an oil bath for 16 h, washed with ethanol and deionized water by centrifugation, and finally dried in a drying oven at 35°C to obtain swollen MCM-22(P).

[0048] The structural formula of the Gemini quaternary ammonium salt cationic surfactant of the present embodiment is as follows:

[0049]

[005...

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Abstract

The invention discloses a method for preparing an MCM-36 molecular sieve under mild conditions, which synthesizes the MCM-36 molecular sieve with a laminated column structure by taking MCM-22(P) as aprecursor, Gemini quaternary ammonium salt cationic surfactants with different structures and hydrophilic properties as an interlayer structure directing agent and tetraethoxysilane (TEOS) as an oxidecolumn precursor. The Gemini quaternary ammonium salt cationic surfactant adopted by the invention has strong hydrophilicity and can retain more moisture between MWW lamellas, so that TEOS can utilize interlayer moisture to hydrolyze and polymerize in an interlayer confinement space under a weak alkaline condition to form a silicon oxide 'column', and the molecular sieve MCM-36 with more regularstructure and centralized pore size distribution is obtained. Moreover, the preparation method is simple, and a hydrolysis step in a traditional method is omitted.

Description

technical field [0001] The invention belongs to the technical field of molecular sieves and porous materials, in particular to a method for preparing MCM-36 molecular sieves under mild conditions. Background technique [0002] MCM-36 molecular sieve is a MWW-type molecular sieve with a pillared structure. 2 , Al 2 O 3 , MgO and other oxides are prepared by pillaring. Compared with the MCM-22 precursor, the MCM-36 molecular sieve retains the original ten-membered ring sinusoidal channel and twelve-membered ring external pore structure. As a result, its BET specific surface area is as high as 2.5 to 3 times that of MCM-22 molecular sieve, and the introduction of mesoporous structure enables it to effectively improve the catalytic performance of reactions involving and generated by macromolecules. In short, due to the unique pore structure in MCM-36 zeolite, its outer pore can be exposed to the greatest extent, and the main active center catalyzing the reaction of larger mo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04C01B39/02
CPCC01B39/04C01B39/026C01P2002/20C01P2002/72C01P2004/03Y02P20/52
Inventor 张智芳冯利军冯亚军
Owner 陕西双翼煤化科技实业集团有限公司
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