Supported carbon-coated bimetallic catalyst and application thereof

Abstract

The invention discloses a preparation method of a supported carbon-coated bimetallic catalyst, which comprises the following steps: (1) weighing a supported bimetallic catalyst, uniformly mixing the supported bimetallic catalyst with water, adding an aqueous solution of a soluble saccharide carbon source compound and an aqueous solution of hydroxyethyl cellulose, dipping at room temperature for 0.5-10 hours, and carrying out vacuum drying until moisture is dried to obtain the supported bimetallic catalyst; a dried product is obtained; (2) carrying out high-temperature roasting on the dried product at 400-1000 DEG C in an inert atmosphere, a hydrogen atmosphere or a vacuum state for 2-20 hours to obtain a roasted product; and (3) reducing the temperature to 100-180 DEG C, and treating the roasted product in an air atmosphere for 4-10 hours to prepare the supported carbon-coated bimetallic catalyst. The catalyst prepared by the invention has a complete carbon layer wrapping metal active component with a proper structure and thickness, is used for preparing alkoxy substituted or phenolic hydroxyl substituted aniline compounds by hydrogenation rearrangement of nitrobenzene compounds, and has high stability and high target product selectivity.

Description

(1) Technical field [0001] The invention relates to a supported carbon-wrapped bimetallic catalyst and its application in the preparation of p-aminophenol by hydrogenation of nitrobenzene. (2) Background technology [0002] In the actual production process of high-end fine chemicals such as pharmaceuticals and electronic chemicals, it is often necessary to carry out catalytic hydrogenation reactions in strong acidic solvents, and the active metal components of the catalysts are prone to dissolution and loss in acidic environments. For example, supported noble metal catalysts have excellent hydrogenation performance and are widely used, but in a strongly acidic reaction environment, noble metals also lose. There are two major problems in the loss of precious metals: irreversible deactivation of the catalyst and residual precious metals in the product. [0003] The irreversible deactivation of the catalyst caused by the loss of noble metal makes it difficult to reuse the cata...

AI Technical Summary

Problems solved by technology

There are two major problems in the loss of precious metals: catalyst irreversible deactivation and precious metals remaining in the product

Although the process is mature, the three wastes are discharged and the product purity is low.

[0007] Catalytic hydrogenation of nitrobenzene to generate hydroxyaniline, and then Bamberger rearrangement reaction in acidic medium, one-step generation of p-aminophenol is a green and efficient synthesis process, but the disadvantage is that the selectivity of the target product p-aminophenol is low, and Hydrogenation catalyst (the main active component is Pt) in a strongly acidic reaction environment, the noble metal is easy to lose, resulting in catalyst deactivation

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