Process for preparing pure silicon MCM-41 molecular sieves

A MCM-41, molecular sieve technology, applied in molecular sieve catalysts, molecular sieve characteristic polymorphic crystalline silicon, chemical instruments and methods, etc., can solve the problems of strong corrosiveness and toxicity of hydrofluoric acid, limit the scope of application, etc., and achieve crystallization The effect of shortened time, narrow pore distribution, good technical effect

Inactive Publication Date: 2005-06-29
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After using hydrofluoric acid, the reaction can be completed at 25-80°C, but hydrofluoric acid is highly corrosive and toxic, which limits the scope of application of this method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Add the required amount of cetyltrimethylammonium bromide (CTMABr), tetraethylammonium hydroxide (TEAOH) and water into a container with a stirring device. After stirring and dissolving at room temperature, add 50 grams of tetraethyl orthosilicate, and add a certain amount of ammonium fluoride. The crystallization temperature is 40° C., under normal pressure, and the crystallization is carried out for 3 hours under stirring. Wherein the relative molar content of each component:

[0013] CTMABr / SiO 2 = 0.2, TEAOH / SiO 2 =0.35,H 2 O / SiO 2 = 45, NH 4 F / SiO 2 =0.02

[0014] After the crystallization, the crystalline product was isolated, dried at 120°C, and then burned at 550°C for 6 hours to obtain a mesoporous pure silicon molecular sieve. It was determined to be MCM-41 molecular sieve by XRD diffraction, and its physical adsorption data are shown in Table 1.

Embodiment 2

[0016] Operate with embodiment 1. Just change the template to tetrapropylammonium hydroxide (TPAOH), the crystallization temperature is 25°C, and the crystallization time is 8 hours. The molar relative content of the components in the raw material is:

[0017] CTMABr / SiO 2 = 0.2, TPAOH / SiO 2 =0.35,H 2 O / SiO 2 = 45, NH 4 F / SiO 2 =0.05

[0018] The obtained molecular sieve was determined to be MCM-41 molecular sieve by XRD diffraction, and its physical adsorption data are shown in Table 1.

Embodiment 3

[0020] Operate with embodiment 1. However, the template is tetrapropylammonium hydroxide (TPAOH), the crystallization temperature is 10°C, and the crystallization time is 18 hours. The relative molar content of the components in the raw material is:

[0021] CTMABr / SiO 2 = 0.2, TPAOH / SiO 2 =0.35,H 2 O / SiO 2 = 45, NH 4 F / SiO 2 =0.1

[0022] The obtained molecular sieve was determined to be MCM-41 molecular sieve by XRD diffraction, and its physical adsorption data are shown in Table 1.

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Abstract

The invention relates to a method for preparing pure silicon MCM-41 molecular sieve. It mainly solves the problems of high crystallization reaction temperature, high crystallization pressure, long crystallization reaction time or strong corrosion of crystallization liquid in the prior art. The present invention solves this problem well by adopting the technical scheme of adding fluoride salt to the reaction system composed of quaternary ammonium base, silicon source and surfactant, and can be used in the industrial production of preparing pure silicon MCM-41 molecular sieve.

Description

technical field [0001] The invention relates to a method for preparing pure silicon MCM-41 molecular sieve. Background technique [0002] The mesoporous crystal material was first synthesized by Mobil Corporation. Its pore size can be controlled in the range of 20-100A, and the pore distribution is uniform, so it is named MCM-41. US Patents US5108725, US5102643, US5098684 and US5057296 describe the synthesis process, reagents, composition, physical and structural properties. [0003] In the above-mentioned patent, adopt quaternary ammonium base, silicon source (or the silicate of quaternary ammonium base) and surfactant (hexadecyltrimethylammonium bromide or its hydroxide) in autoclave , Crystallization at 100-150°C for 2-7 days. [0004] The principle of crystallization is that silicon oxide or silicon-aluminum mixed oxide is attracted on the surface of micelles (micelles are produced by dissolving surfactants in water), and roasting can f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/035C01B37/02
Inventor 张惠宁曹静高焕新
Owner CHINA PETROLEUM & CHEM CORP
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