SiO2 supported nanometer silver catalyst, preparing method and applications thereof

Abstract

The invention discloses a catalyst for loading silver on SiO2, a preparation method and application in a selective catalytic hydrogenation of chloro-aromatic compounds, nitryl-aromatic ene, nitryl-aromatic aldehydes, nitryl-aromatic ketone, and nitryl-aromatic polyamide. The synthetic method is that tetraethoxysilane and aminopropyl-triethoxysilane are added by weight proportion of 1: 0.1-1: 25 into an ammonia solution containing definite AgNO3, then the solution is stirred to form gelatinate under room temperature and dried under 100-200 DEG C for about 4-12 hours, thus obtaining the catalyst. The synthetic catalyst of the invention solves two problems of current catalytic hydrogenation of aromatic nitro-compounds: (1) a secondary reaction of dechlorination is generated during the hydrogenation of chloronitrobenzenes of aromatic nitro-compounds; (2) the selectivity of reaction is poor when alkene, aldehydes, ketone, nitrile and amide groups coexist.

Description

technical field [0001] The invention relates to a silicon dioxide-supported nano-silver catalyst, a preparation method of the catalyst and its application in the selective hydrogenation of nitroaromatic compounds to prepare aminoaromatic compounds. Background technique [0002] Efficient and selective catalytic hydrogenation of aromatic nitro compounds is of great significance in the industrial field. Aminoaromatic compounds are very important chemical intermediates, which can be used to synthesize various fine chemicals such as pesticides, drugs, and photoelectric functional molecules. At present, the preparation methods of aminoaromatic compounds include: metal powder-acid chemical reduction method, electrochemical reduction method, and catalytic hydrogenation method. [0003] The main problems with these methods are: [0004] 1. The metal powder-acid chemical reduction method produces a large amount of inorganic salt waste, which pollutes the environment and does not me...

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Problems solved by technology

[0004] 1. The metal powder-acid chemical reduction method produces a large amount of inorganic salt waste, which pollutes the environment and does not meet the requirements of green chemistry

Electrochemical reduction method has high requirements on electrodes, electrolyte and electrolytic cell, and is not suitable for mass production

[0005] 2. The catalysts used in the catalytic hydrogenation method are Raney nickel and platinum. During the production and use of Raney nickel catalysts, a large amount of alkaline wastewater is generated, and there are disadvantages such as difficult storage, inconvenient transportation, and poor reusability, especially product selectivity. Can not reach 100%, the generated by-products seriously affect product quality

Although nano-gold catalysts have relatively good results for this type of reaction, the price of gold catalysts is high

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