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Method for improving stability and activity of catalyst for gas-phase epoxidation of propylene

A catalyst and epoxidation technology, which is applied in the field of preparation of gold-silver alloy catalysts, can solve problems such as low selectivity, difficulty in ensuring stability, and increased catalyst cost, so as to achieve the effect of improving activity and reducing catalyst cost

Inactive Publication Date: 2015-11-04
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, although the gold-loaded titanium-silicon molecular sieve catalyst prepared by the deposition-precipitation method has higher catalytic activity than other catalysts, the catalyst still has certain deactivation problems (Document 1: J.Catal.2012, 287, 178–189)
Recently, there have been reports about the use of ionic liquid-enhanced biomass methods to synthesize higher-stability supported gold catalysts, but the catalysts need to be used at 300 degrees, with high energy consumption and low selectivity (<80%); in addition, Ionic liquids are expensive, and the biomass reduction method used cannot selectively deposit gold particles near the active site titanium of the titanium-silicon molecular sieve, which wastes a part of the gold and invisibly increases the cost of the catalyst (Document 2: Ind.Eng.Chem. Res.2011, 50, 9019–9026)
In addition, the addition of metal promoters such as K, Ba, and Cs can improve the activity of the catalyst, but it is difficult to ensure its stability.
(Document 3: Catal. Today. 2009, 147, 186–195) In CO low-temperature catalysis and NOx systems, gold-silver catalysts are prepared step by step by deposition and precipitation, but the gold-silver content used is relatively high, and the gold-silver ratio is close to 1:1 and dried at a higher temperature, the alloy particles are larger (Document 4: J.Catal.2011, 281, 40–49, Document 5: Applied Catalysis B: Environmental, 2015, 162, 11–20)

Method used

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  • Method for improving stability and activity of catalyst for gas-phase epoxidation of propylene
  • Method for improving stability and activity of catalyst for gas-phase epoxidation of propylene
  • Method for improving stability and activity of catalyst for gas-phase epoxidation of propylene

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Embodiment 1

[0100] Preparation of gold-silver catalyst

[0101] Take 0.7g of unbaked titanium-silicon molecular sieve and place it in a 250mL beaker, add 35mL of water and 0.67mL of concentration to 3.0×10 -7 mol / mL of AgNO 3 The solution was stirred in a water bath at 80°C for 30 minutes, then adjusted to pH 9 with 0.1mol / L sodium hydroxide, and aged for 2 hours. After centrifugation, it was dried in a vacuum at 25°C for 4 hours. The solid after drying is placed in the 250mL beaker, add 35mL water, 0.063g urea and 0.07mL concentration and be the chloroauric acid solution of 0.003mol / L, under 90 degree of water bath conditions, dark stirring 6 hours, after centrifugation, in 25 Dry under vacuum in the dark for 8 hours.

Embodiment 2

[0103] Preparation of gold-silver catalyst

[0104] Take 0.7g of unbaked titanium-silicon molecular sieve and place it in a 250mL beaker, add 35mL of water and 1mL of concentration to 4.63×10 -6 mol / mL of AgNO 3 solution, stirred in a 95-degree water bath for 30 minutes in the dark, then adjusted the pH to 7 with 0.1mol / L sodium hydroxide, aged for 2 hours, and dried in a vacuum at 80 degrees for 4 hours after centrifugation; the dried solid Place in a 250mL beaker, add 35mL water, 0.063g urea and 0.07mL chloroauric acid solution with a concentration of 0.003mol / L, stir in a 90-degree water bath for 6 hours in the dark, centrifuge and dry in a vacuum at 25 degrees in the dark 8 hours.

Embodiment 3

[0106] Preparation of gold-silver catalyst

[0107] Take 0.7g of unbaked titanium-silicon molecular sieve and place it in a 250mL beaker, add 35mL of water and 1mL of concentration to 4.63×10 -7 mol / mL of AgNO 3 solution, stirred in a 95-degree water bath for 30 minutes in the dark, then adjusted the pH to 12 with 0.1mol / L sodium hydroxide, aged for 2 hours, centrifuged and dried in a vacuum at 5 degrees in the dark for 4 hours; the dried solid Place in a 250mL beaker, add 35mL water, 0.063g urea and 0.07mL chloroauric acid solution with a concentration of 0.003mol / L, stir for 6 hours in a water bath at 30°C in the dark, centrifuge and dry in a vacuum at 25°C in the dark 8 hours.

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Abstract

The invention discloses a method for improving the stability and the activity of a gold catalyst for preparing propylene oxide through propylene epoxidation. Silver metals are added to the gold catalyst to form nanometer gold silver alloy particles of which the particle sizes are small, and the alloy is used for changing oxygen adsorption, so that the content and the nature of coke are further improved, and the catalyst activity and the stability of a gold-silver alloy catalyst are greatly improved.

Description

technical field [0001] The invention relates to a catalyst, in particular to a preparation method of a gold-silver alloy catalyst suitable for propylene epoxidation to prepare propylene oxide. Background technique [0002] Propylene oxide (PO), as the third largest organic chemical product in the production of propylene derivatives after polypropylene and acrylonitrile, is widely used in the preparation of derivatives such as polyurethane and polyester resins. At present, the main methods of producing PO in industry are chlorohydrin method and co-oxidation method. However, the chlorohydrin method does not meet the requirements of today's green environmental protection due to its great corrosion on equipment and the production of a large amount of waste water and chlorine-containing by-products. However, the economics of the co-oxidation method is restricted by a large number of by-products. Recently, the emerging H 2 o 2 Due to the complex operation process and expensive...

Claims

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Application Information

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IPC IPC(8): B01J23/52
Inventor 周兴贵杨佳冯翔张志华段学志钱刚陆梦科
Owner EAST CHINA UNIV OF SCI & TECH
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