Catalyst for preparing p-xylene as well as preparation method and application thereof

A technology of paraxylene and catalyst, applied in the field of catalysis, to achieve the effects of slowing down deactivation, not easy to migrate, and high selectivity

Pending Publication Date: 2020-08-25
CHINA NAT OFFSHORE OIL CORP +4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, Nishiyama et al. also used repeated hydrothermal synthesis to prepare polycrystalline silicalite-1 as a coated ZSM-5 catalyst, which was applied to toluene / methanol = 1, 400°C for 60 minutes, and the selectivity to the product p-xylene was greater than 99.9%. The selectivity of the catalyst precursor without coating can only reach about 40% (see literature: "Van Vu D., Miyamoto M., Nishiyama N., et al.Catalytic activities and structures of silicalite-1 / H-ZSM-5zeolite ")

Method used

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  • Catalyst for preparing p-xylene as well as preparation method and application thereof
  • Catalyst for preparing p-xylene as well as preparation method and application thereof
  • Catalyst for preparing p-xylene as well as preparation method and application thereof

Examples

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Embodiment 1

[0093] The core-shell mass ratio of the catalyst described in this embodiment is 1:0.51, the hydrogenation metal is Pt, and the mass percentage of the hydrogenation metal Pt in the catalyst is 0.016%; the preparation method of the catalyst comprises the following steps:

[0094] (1) Prepare the nuclear phase Pt@ZSM-5 molecular sieve, the preparation process includes the following steps:

[0095] (a) Add 10 g of ethyl orthosilicate and 26 g of tetrapropylammonium hydroxide into 10 g of deionized water at 35°C and stir for 10 min, marked as solution A;

[0096] (b) Dissolve 0.1332g of aluminum sulfate (the molar ratio of silica to alumina is 400) into 10g of deionized water, marked as solution B;

[0097] (c) Slowly add solution B dropwise to solution A, and continue stirring for 6 hours to obtain a mixed solution;

[0098] (d) Dissolving 0.0095g tetraammine platinum nitrate in 10.8g deionized water to obtain an aqueous hydrogenation metal source solution;

[0099] (e) Slowly ...

Embodiment 2

[0105] The core-shell mass ratio of the catalyst described in this embodiment is 1:1.08, the hydrogenation metal is Pt, and the mass percentage of hydrogenation metal Pt in the catalyst is 0.014%;

[0106] In the preparation process of the catalyst described in this example, the nuclear phase Pt@ZSM-5 molecular sieve prepared in Example 1 was used as a raw material, and an epitaxial growth was performed to form an S-1 molecular sieve to obtain the catalyst; the preparation method included the following steps:

[0107] (a') Mix 3.47g ethyl orthosilicate, 0.68g tetrapropylammonium hydroxide, and 52g water, stir and hydrolyze at 35°C for 7 hours to obtain a mixed solution;

[0108] (b') Add 1 g of the Pt@ZSM-5 powder prepared in Example 1 into the mixed solution obtained in step (a'), continue stirring for 1 h, and then transfer it to a 100 mL crystallization kettle with a polytetrafluoroethylene lining , crystallized in a rotary crystallization oven at 170°C at a speed of 20r / mi...

Embodiment 3

[0110] The core-shell mass ratio of the catalyst described in this embodiment is 1:1.51, the hydrogenation metal is Pt, and the mass percentage of hydrogenation metal Pt in the catalyst is 0.011%;

[0111] In the preparation process of the catalyst described in this example, the nuclear phase Pt@ZSM-5 molecular sieve prepared in Example 1 was used as a raw material, and an epitaxial growth was performed to form an S-1 molecular sieve to obtain the catalyst; the preparation method included the following steps:

[0112] (a') Mix 5.21g ethyl orthosilicate, 1.02g tetrapropylammonium hydroxide, and 52g water, and stir and hydrolyze at 35°C for 7 hours to obtain a mixed solution;

[0113] (b') Add 1 g of the Pt@ZSM-5 powder prepared in Example 1 into the mixed solution in step (a'), continue stirring for 1 h, then transfer to a 100 mL crystallization kettle with a polytetrafluoroethylene liner, at 170 ℃ Rotary crystallization oven at 20r / min for 72 hours of crystallization. After th...

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Abstract

The invention relates to a catalyst for preparing p-xylene as well as a preparation method and application of the catalyst. The catalyst is a core-shell structure molecular sieve and comprises an inner core molecular sieve and a shell layer molecular sieve coating the surface of the inner core molecular sieve, wherein the inner core molecular sieve is a ZSM-5 molecular sieve, the shell layer molecular sieve is an S-1 molecular sieve, and hydrogenation metal is packaged in the inner core molecular sieve; the catalyst has high conversion rate and selectivity to the product p-xylene in the process of catalyzing the alkylation reaction of toluene and methanol, the carbon deposition rate of the catalyst in the catalytic process is obviously reduced, and the catalyst has high stability.

Description

technical field [0001] The invention belongs to the technical field of catalysis, and relates to a catalyst for preparing p-xylene, a preparation method and application thereof. Background technique [0002] Paraxylene (PX) is an important organic chemical raw material, mainly used to produce polyester. In recent years, the polyester industry has developed rapidly, so the demand for p-xylene has also been increasing. The typical method of producing p-xylene is catalytic reforming of naphtha, which can only obtain a thermodynamically balanced xylene mixture. It needs further cryogenic crystallization or simulated moving bed adsorption separation technology to obtain high-concentration p-xylene. High, high energy consumption. [0003] At present, the isomerization of mixed xylenes, the transalkylation technology of C9 aromatics and the selective disproportionation of toluene are the main methods to increase the production of p-xylene in industrial production. In addition, d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/44B01J29/035C07C15/08C07C2/86
CPCB01J29/005B01J35/0086C07C2/864B01J29/035B01J29/44B01J2229/62C07C15/08Y02P20/52
Inventor 李孝国侯章贵郭新闻张安峰常洋齐美美李永恒曹辉韩国栋张永坤
Owner CHINA NAT OFFSHORE OIL CORP
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