Multilevel pore heteroatom MFI-type molecular sieve and preparation method thereof

A technology of heteroatom and molecular sieve, which is applied in the field of multi-level pore heteroatom MFI molecular sieve and its preparation, can solve the problems of unfavorable template effect, weak force, and difficult uniform dispersion of carbon materials, so as to reduce synthesis cost and improve catalytic performance. Activity, the effect of resolving diffusion limitations

Inactive Publication Date: 2017-06-20
YANGTZE UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these carbon materials are generally not easy to uniformly disperse into the entire synthesis system, and the interaction between them and the inorganic precursor species is weak, which is not conducive to the exertion of their template function.

Method used

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  • Multilevel pore heteroatom MFI-type molecular sieve and preparation method thereof
  • Multilevel pore heteroatom MFI-type molecular sieve and preparation method thereof
  • Multilevel pore heteroatom MFI-type molecular sieve and preparation method thereof

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preparation example Construction

[0021] One aspect of the present invention provides a method for preparing a multi-level pore heteroatom MFI molecular sieve, comprising the following steps:

[0022] S1, preparation of xerogel:

[0023] In the state of stirring, mix the silicon source, 0.01-0.5mol / L dilute acid, mesoporous carbon source and deionized water evenly, and then add the alkali source according to the molar ratio of the alkali source to the mesoporous carbon source of 0.01-1 Gel forming, drying and grinding the gel to obtain xerogel.

[0024] Preferably, in step S1, the dilute acid is one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, formic acid, acetic acid, oxalic acid, and propionic acid;

[0025] Preferably, in step S1, when preparing the acidic xerogel, silicon source: acid: mesoporous carbon source: deionized water is prepared in a molar ratio of 1:0.001-0.02:0.01-2:15-100;

[0026] Preferably, in step S1, the silicon...

Embodiment 1

[0050] S1. Preparation of xerogel: Take 83.3g of tetraethyl silicate in 28.8g of 0.05mol / L hydrochloric acid, stir at 20-30°C for 3 hours to obtain solution A; take 71.9g of Tween 40 and dissolve in 180g of deionized water , placed in solution A, and continued to stir for 3 hours to obtain solution B; then, 3.0 g of tetrapropylammonium hydroxide solution (20%) was added to solution B to obtain a gel, which was dried overnight and ground to obtain a xerogel.

[0051] S2. Sulfuric acid pre-carbonization of dry gel: take 20 g of the dry gel prepared in step S1 and put it into 300 mL of 5% sulfuric acid solution, stir at 20-30 °C for 12 hours, then evaporate the solution to dryness at 120 °C, and finally heat it at 175 °C Lower carbonization for 72h, and grind to obtain black powder;

[0052] S3. High-temperature carbonization of xerogel: put the black powder prepared in step S2 into a tube furnace, and raise the temperature from 25°C to 600°C for 24h under pure nitrogen gas (200...

Embodiment 2

[0056] The method for preparing multi-stage porous titanium-silicon molecular sieves in this example is basically the same as in Example 1, except that in step S1, the mesoporous carbon source is Sipan 60, and Siban 60 / SiO 2 The molar ratio is 0.16; step S2: take 20g of the xerogel prepared in step S1, put it into 100mL of sulfuric acid solution with a concentration of 15%, stir at 20-30°C for 24h, then evaporate the solution at 110°C, and finally dry it at 200°C Carbonize for 4 hours and grind to obtain a black powder; in step S3, carbonize for 60 hours at 400°C under pure argon (60mL / min); in step S4, the molar ratio of Ti / Si is 0.001, and the crystallization temperature is 200°C. The curing time is 8h, the firing temperature is 500°C, and the firing time is 12h.

[0057] The nitrogen adsorption-desorption curve of the obtained multi-level porous titanium-silicon molecular sieve is as follows Figure 4 As shown, its BJH pore distribution is as Figure 5 shown. It can be s...

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Abstract

The invention relates to a preparation method of a multilevel pore heteroatom MFI-type molecular sieve. The preparation method comprises the following steps: S1, preparing xerogel; S2, performing sulfuric acid pre-carbonization for the xerogel; S3, carbonizing the xerogel at a high temperature to obtain C-SiO2 complex; S4, uniformly mixing a compound containing heteroatom, a micropore template agent, an alkaline source and deionized water, adding the C-SiO2 complex, sufficiently mixing, crystallizing, washing, drying, roasting, and obtaining the multilevel pore heteroatom MFI-type molecular sieve. The multilevel pore heteroatom MFI-type molecular sieve has the advantages that (1) compounds such as tween, span or triton are used as a mesoporous carbon source, so that the synthetic cost is decreased; and (2) the xerogel is subjected to the sulfuric acid pre-carbonization and high-temperature carbonization to obtain the C-SiO2 complex sufficiently coated with a silicon source and carbon material, the heteroatom is easier to anticipate in the crystallization of the molecular sieve in the liquid-phase mechanical drive process in an ion form, the amount of the heteroatom entering a molecular sieve skeleton is increased, the catalytic activity is improved, the dispersion limitation of intrinsic micropores of zeolite on the catalytic reaction is effectively solved, and the application in the field of macromolecular catalysis is enlarged.

Description

technical field [0001] The invention belongs to the technical field of molecular sieve preparation. Specifically, it relates to a multi-level channel heteroatom MFI molecular sieve and a preparation method thereof. Background technique [0002] Zeolite materials with MFI two-dimensional pore structure play a very important role in the field of catalysis and fine chemical industry. In the 1980s, Enichem introduced the transition metal titanium into the molecular sieve framework for the first time, synthesized a titanium-silicon molecular sieve (TS-1) with an MFI structure, and successfully used it in the selective oxidation of hydrocarbons with the participation of hydrogen peroxide, making the molecular sieve Expanding from the field of acid-base catalysis to the field of redox catalysis has become a milestone in molecular sieve catalysis. Since then, heteroatom molecular sieves containing metal ions have emerged continuously, and ZSM-5 molecular sieves containing Cu, V, F...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/08C01B39/04C01B37/02
CPCC01B39/085C01B37/005C01B37/02C01B39/04C01B39/08C01B39/087C01P2002/72C01P2006/12C01P2006/14C01P2006/17
Inventor 李颢刘晓雪张瑞雪郭彬彬熊招娣盛全张秉毅
Owner YANGTZE UNIVERSITY
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