Method for preparing hierarchical porous isomorphous substitution Ga-ZSM-5 molecular sieve catalyst

A technology of isomorphic substitution and molecular sieve, which is applied in the application field of conversion of benzene and methanol into toluene and xylene, can solve the problems of poor service life of the catalyst, affecting the diffusion performance of the pores, and reducing the utilization rate of methanol, etc. Toluene selectivity, high catalyst stability, and the effect of suppressing ethylbenzene by-products

Active Publication Date: 2018-08-24
ZHEJIANG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Studies have shown that when ZSM-5 molecular sieve is directly used to catalyze the alkylation reaction of benzene and methanol, there are two main problems: the formation of by-product ethylbenzene and the po

Method used

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  • Method for preparing hierarchical porous isomorphous substitution Ga-ZSM-5 molecular sieve catalyst
  • Method for preparing hierarchical porous isomorphous substitution Ga-ZSM-5 molecular sieve catalyst
  • Method for preparing hierarchical porous isomorphous substitution Ga-ZSM-5 molecular sieve catalyst

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Example 1: 0.0680g aluminum isopropoxide, 12.0g tetrapropyl ammonium hydroxide aqueous solution (25wt%), 13.2ml tetraethyl orthosilicate, 1.2g hexadecyltrimethoxysilane (85wt%) and 50ml Ethanol was mixed in a beaker and stirred at 20°C until a gel was formed; the gel was dried at 20°C for 24h, and then the gel was transferred to a PTFE liner (A) with a volume of 50ml, and another volume of 250ml was taken PTFE liner (B) and add 40ml of deionized water to it, then transfer the above-mentioned liner (A) to the liner (B), at this time the deionized water is between the two liners; Transfer the combined lining to a 250ml stainless steel hydrothermal kettle, crystallize at 170°C for 72h; filter and wash, dry at 100°C for 4h, and roast at 550°C for 10h; press the calcined catalyst and crush it , sieve, and take a catalyst with a particle size of 20 to 40 meshes to obtain a hierarchically porous ZSM-5 molecular sieve (Si / Al=180) with 0% Ga substitution.

Embodiment 2

[0032] Embodiment 2: with 0.0340g aluminum isopropoxide, 0.0421g gallium nitrate, 12.0g tetrapropyl ammonium hydroxide aqueous solution (25wt%), 13.2ml orthosilicate ethyl ester, 1.2g hexadecyltrimethoxysilane ( 85wt%) and 50ml of ethanol were mixed in a beaker and stirred at 20°C until a gel was formed; the gel was dried at 20°C for 24h, and then the gel was transferred to a polytetrafluoroethylene liner (A) with a volume of 50ml, Take another PTFE liner (B) with a volume of 250ml and add 40ml of deionized water to it, then transfer the above-mentioned liner (A) to the liner (B), at this time, the deionized water is located in the two inner between the linings; transfer the combined lining to a 250ml stainless steel hydrothermal kettle, crystallize at 180°C for 72h; filter and wash, dry at 100°C for 4h, and roast at 550°C for 10h; the calcined catalyst Perform tableting, crushing, and sieving, and take a catalyst with a particle size of 20 to 40 meshes to obtain a hierarchica...

Embodiment 3

[0033] Embodiment 3: with 0.0204g aluminum isopropoxide, 0.0589g gallium nitrate, 12.0g tetrapropyl ammonium hydroxide aqueous solution (25wt%), 13.2ml orthosilicate ethyl ester, 1.2g hexadecyltrimethoxysilane ( 85wt%) and 50ml of ethanol were mixed in a beaker and stirred at 20°C until a gel was formed; the gel was dried at 20°C for 24h, and then the gel was transferred to a polytetrafluoroethylene liner (A) with a volume of 50ml, Take another PTFE liner (B) with a volume of 250ml and add 40ml of deionized water to it, then transfer the above-mentioned liner (A) to the liner (B), at this time, the deionized water is located in the two inner between the linings; transfer the combined lining to a 250ml stainless steel hydrothermal kettle, crystallize at 180°C for 72h; filter and wash, dry at 100°C for 4h, and roast at 550°C for 10h; the calcined catalyst Perform tableting, crushing, and sieving, and take a catalyst with a particle size of 20 to 40 meshes to obtain a hierarchica...

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Abstract

The invention discloses a method for preparing a hierarchical porous isomorphous substitution Ga-ZSM-5 molecular sieve catalyst. The method comprises the following steps: tetraethyl orthosilicate, gallium nitrate, aluminum isopropoxide, tetrapropylammonium hydroxide (TPAOH), hexadecyltrimethoxysilane (HTS) and ethanol are mixed according to a certain ratio, and are stirred until a gel is formed, and the gel is crystallized, reacted and calcined to obtain the catalyst. The catalyst has the advantages of excellent effect, high benzene conversion activity, high toluene and xylene selectivity, high stability and low ethylbenzene selectivity when used in an alkylation reaction of benzene with methanol to synthesize toluene and xylene; and other metals or hydrogen atmosphere is not needed, so the separation of the ethylbenzene byproduct is omitted, the production cost and the energy consumption, are reduced, and the increase of the economical property of a process route for the alkylation ofbenzene and methanol to prepare toluene and xylene is facilitated.

Description

technical field [0001] The invention relates to a preparation method of a multi-level porous isomorphic substituted Ga-ZSM-5 molecular sieve catalyst and its application in the alkylation reaction of aromatic hydrocarbons, especially the application in the conversion of benzene and methanol into toluene and xylene. Background technique [0002] Toluene and xylene are widely used in the chemical industry as basic petrochemical raw materials, and play a pivotal role in the development of modern petrochemical industry. Among them, toluene is an intermediate in the synthesis of many organic chemical products, it can also be used as a high-octane gasoline additive, and it is also an excellent solvent. Among xylenes, p-xylene (PX), as the upstream reactant of dimethyl terephthalate (DMT), is the main raw material for synthetic polyester, and occupies an extremely important position in the world's synthetic polyester, fiber and plastic fields; Ortho-xylene and meta-xylene are used...

Claims

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Application Information

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IPC IPC(8): B01J29/87B01J29/40C07C2/86C07C15/06C07C15/08
CPCB01J29/405B01J29/87B01J2229/18C07C2/864C07C2529/40C07C2529/87C07C15/06C07C15/08Y02P20/52
Inventor 李小年王清涛韩文雯张群峰吕井辉
Owner ZHEJIANG UNIV OF TECH
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