Nanosized gold catalyst used for preparing propylene oxide by direct propylene oxidation and preparation method thereof

A propylene oxide and nano-gold technology, which is applied in catalyst activation/preparation, physical/chemical process catalyst, molecular sieve catalyst, etc., can solve the problems of low catalyst activity and easy deactivation of catalyst.

Inactive Publication Date: 2009-09-16
CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since then, a series of nano-gold catalysts supported by titanium-silicon oxides with different structures have been widely studied, among which nano-gold catalysts supported by mesoporous molecular sieves Ti-MCM-41, Ti-MCM-48, Ti-TUD, etc. have high initial activity. , but the main problem of the catalyst is that it is easy to deactivate
The nano-gold catalyst supported by microporous molecular sieve TS-1 has good stability, but the activity of the catalyst is low

Method used

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  • Nanosized gold catalyst used for preparing propylene oxide by direct propylene oxidation and preparation method thereof
  • Nanosized gold catalyst used for preparing propylene oxide by direct propylene oxidation and preparation method thereof
  • Nanosized gold catalyst used for preparing propylene oxide by direct propylene oxidation and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1: Preparation of mesoporous-microporous composite titanium-silicon molecular sieve carrier

[0029] Dissolve 1.02 grams of tetrabutyl titanate in an appropriate amount of isopropanol and add it to 62.4 grams of tetraethyl orthosilicate, stir and mix evenly, place in an ice-water bath, slowly add 60 grams of tetrapropyl titanate dropwise under vigorous stirring Ammonium hydroxide solution (20 wt%) was added thereto. Continue to stir the reaction for 1-2 hours after the dropwise addition, and then slowly raise the temperature to about 70 degrees, evaporate and remove the isopropanol and the ethanol solvent produced by the hydrolysis of ethyl orthosilicate therein. Finally, add 60 grams of water, continue stirring and reacting for 1-2 hours, then transfer to a PTFE-lined autoclave, react statically in a drying oven at 100°C for 3 hours, then cool to room temperature to obtain a microporous molecular sieve precursor sol. 33 g of cetyltrimethylammonium bromide were...

Embodiment 2

[0030] Embodiment 2: the preparation of nano gold catalyst

[0031] Heat 100ml of chloroauric acid solution (2.4mM) to 70°C with 1M N 2 CO 3 The pH of the solution was adjusted to 8.9. Add 1 gram of the titanium-silicon molecular sieve carrier prepared in Example 1 under vigorous stirring, and after stirring and reacting for 15 minutes, add 5ml of 0.04mol / L Ba(NO 3 ) 2 The solution was stirred at the same temperature for 45 minutes. After being cooled to room temperature, the obtained sample was separated by suction filtration, washed with 50 milliliters of distilled water, dried overnight in a vacuum oven at room temperature, and finally calcined at 300 ° C for 4 hours to obtain a nano-gold catalyst. The TEM photo of the catalyst is attached image 3 As shown, the average particle size of the gold nanoparticles is 2-3nm.

Embodiment 3

[0032] Example 3: Preparation of Propylene Oxide by Direct Oxidation of Propylene under Hydrogen / Oxygen Coexistence Conditions

[0033]The catalytic performance of nano-gold catalysts was evaluated on a quartz tube microreactor with an inner diameter of 8 mm. The catalyst consumption is 0.3g, the flow rates of hydrogen, oxygen, propylene and nitrogen are 3.5, 3.5, 3.5 and 24.5ml / min respectively, the space velocity is 7000, and the reaction pressure is 0.1MPa. Before starting the reaction, the catalysts were separately treated with 12.5 Vol% H at 250 °C 2 and O 2 Pretreatment for 30min, then lower the temperature to 150°C in N2 atmosphere, and pass H 2 、C 3 h 6 and O 2 start reacting. The reaction products were analyzed online by gas chromatography equipped with FID and TCD. Catalyst performance was measured and compared in terms of propylene conversion, propylene oxide selectivity, and propylene oxide formation rate. The catalytic reaction results are listed in Table ...

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Abstract

The invention provides a catalyst for preparing propylene oxide by direct propylene oxidation on the condition of hydrogen / oxygen coexistence and a preparation method thereof; the invention is characterized in that the catalyst takes a titanium silicon molecular sieve with a mesopore-millipore composite structure as the carrier and is prepared by a deposition-precipitation method. The titanium silicon molecular sieve with the mesoporous-millipore composite structure has the structural advantages of the large specific surface and pore size of the mesoporous molecular sieve as well as the regular pore wall structure of the milliporous molecular sieve and highly-dispersed quadridentate titanium (IV); nanosized gold catalyst which is prepared by taking the titanium silicon molecular sieve with the composite structure as the carrier has higher catalytic activity than that of the Nanosized gold catalyst which takes pure mesoporous titanium silicon molecular sieve or milliporous titanium silicon molecular sieve as the carries, moreover, the stability of the catalyst is greatly improved. By adding alkaline earth metal to the catalyst, the loading capacity of gold can be relatively improved, thereby increasing the converting rate of propylene and the generating rate of propylene oxide.

Description

technical field [0001] The invention provides a nano-gold catalyst for directly oxidizing propylene to produce propylene oxide under the coexistence of hydrogen and oxygen and a preparation method thereof. Background technique [0002] Propylene oxide is the third largest propylene derivative next to polypropylene and acrylonitrile. The largest use is for the production of polyether polyols for further processing to produce polyurethane; it can also produce propylene glycol, which is widely used as a solvent, Lubricants, antifungal agents, etc. are widely used in food, tobacco and pharmaceutical industries. In addition, propylene oxide is also used in the production of nonionic surfactants, oil field demulsifiers, pesticide emulsifiers and wetting agents, etc. At present, the industrial production of propylene oxide mainly includes the chlorohydrin method and the Halcon method. These two methods respectively have the problems of serious environmental pollution and the produ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/89B01J37/02
Inventor 张小明余欢索继栓
Owner CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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