Preparation method of high-activity low-byproduct propylene gas-phase epoxidation catalyst

An oxidation system and catalyst technology, applied in the direction of physical/chemical process catalysts, molecular sieve catalysts, chemical instruments and methods, etc., can solve the problems of ineffective decomposition of hydrogen peroxide, limit the number of Ti active sites in TS-1 molecular sieve, and avoid multi-step The treatment process, excellent catalytic activity, and the effect of simplifying the preparation process

Inactive Publication Date: 2021-06-01
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

The research results show that in order to obtain highly active Au species and as many epoxidized Ti centers as possible, and in order to get closer to the reactants, most of the existing technologies use titanium-silicon molecular sieves to be synthesized and then modified, thus exposing More Ti active sites and generate more defect sites for Au loading, and amorphous Ti species can lead to ineffective decomposition of hydrogen peroxide
[0004] The existing technology shows that the theoretical limit of the framework titanium content in the titanium-silicon molecular sieve is 2.5%, that is, the silicon-titanium molar ratio is 40:1. This result limits the number of Ti active sites in the TS-1 molecular sieve
Some researchers have achieved the purpose of increasing the framework titanium by reducing the ratio of silicon to titanium, but at the same time it will also bring about a large number of amorphous titanium species.

Method used

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  • Preparation method of high-activity low-byproduct propylene gas-phase epoxidation catalyst
  • Preparation method of high-activity low-byproduct propylene gas-phase epoxidation catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Add 0.2g of soluble starch and 38g of water into the beaker and stir, then add 44g of 25wt% TPAOH aqueous solution and 46.2g of tetraethyl orthosilicate in sequence, and hydrolyze at 30°C for 3h to obtain a silicon source hydrolysis mixture; 3.8g of titanic acid Tetrabutyl ester was dissolved in 18.7g of isopropanol, and then stirred for 30min to obtain the titanium source hydrolysis mixture; and alcohol was removed at 80°C for 1.5h, 50.2g of water and 0.045g of sodium sulfite were stirred for 30min, and the obtained transparent glue was filled Put the solution into the crystallization kettle for crystallization, put the resulting solution into the crystallization kettle, and crystallize at 175°C for 3 days. After washing and drying, the crystallized product is washed with 1M HCl aqueous solution (the liquid-solid ratio is 50ml g -1 ), calcined in air at 550°C for 6h, and obtained a TS-1 sample with a Si / Ti ratio of 31.2 after XRF testing.

[0046] The Au loading proces...

Embodiment 2

[0048] Repeat Example 1, replace the soluble starch in the defect site auxiliary agent in the preparation process of TS-1 with sodium carboxymethylcellulose, polyacrylamide, polyethyleneimine, the amount of the component substances remains unchanged, after crystallization, After washing and drying, use 1M HCl aqueous solution to wash (the liquid-solid ratio is 50ml g -1 ), calcined in air at 550°C for 6h, obtained TS-1 samples with Si / Ti ratios of 31.6, 31.9, and 31.8 after XRF testing, and then carried out Au loading to obtain catalyst numbers of 0.38%Au / TS-1-G, 0.38% Au / TS-1-H, 0.38% Au / TS-1-I.

Embodiment 3

[0050] Repeat Example 1, the tetraethyl orthosilicate in the TS-1 preparation process is replaced by tetramethyl orthosilicate, tetrapropyl orthosilicate, the amount of tetrabutyl orthosilicate component material remains unchanged, After crystallization, adopt 1M HCl aqueous solution washing after washing, drying (liquid-solid ratio is 50ml g -1 ), calcined in air at 550°C for 6h, obtained TS-1 samples with Si / Ti ratios of 31.9, 32.0, and 31.8 after XRF testing, and carried out Au loading to obtain catalyst numbers 0.38%Au / TS-1-J, 0.38% Au / TS-1-K, 0.38% Au / TS-1-L.

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PUM

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Abstract

The invention discloses a preparation method of a high-activity low-byproduct propylene gas phase epoxidation catalyst. In the preparation process of the catalyst, a defect site auxiliary agent and an S auxiliary agent are added, titanium-rich defect sites suitable for Au loading are obtained, amorphous species on the catalyst are stabilized by S, then the high-activity propylene gas phase epoxidation catalyst is obtained, and alkali metal ions introduced at the same time with the S auxiliary agent can reduce the production probability of by-products, so that the conversion rate of propylene, the selectivity of PO and the hydrogen efficiency are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of catalytic synthesis, and in particular relates to a preparation method for a propylene gas-phase epoxidation catalyst. Background technique [0002] At present, the production units of the liquid-phase HPPO process all use methanol as the solvent. However, the methanol solvent also brings a lot of trouble to the HPPO process. First, methanol is prone to solvolysis side reactions with propylene oxide products to generate high-boiling point propylene glycol monomethyl ether and other by-products. These by-products not only seriously reduce the selectivity of propylene oxide, but also increase the difficulty of wastewater treatment. Secondly, methanol solvent must be recycled, and complex refining treatment (including hydrogenation, rectification and resin adsorption) is required before recycling, which leads to complex HPPO process and high investment and energy consumption. What's worse, the circulating...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/89C07D301/10C07D303/04
CPCB01J29/89B01J2229/18B01J2229/183C07D301/10C07D303/04Y02P20/52
Inventor 黄家辉贾玉华吕强龙化云
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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