Carbon-supported multi-component catalyst and preparation method and application thereof

Abstract

The invention provides a carbon-supported multi-component catalyst and a preparation method thereof. The catalyst is prepared from a carrier and metal active components loaded on the carrier. The carrier is activated carbon. The metal active components comprise palladium, platinum and a transition metal element assistant. Based on the mass of the carrier, namely, the activated carbon, the capacity of palladium ranges from 0.5 wt% to 5.0 wt%, the capacity of platinum ranges from 0.5 wt% to 5.0 wt%, and the capacity of the transition metal element assistant ranges from 0.1 wt% to 2.5 wt%. Meanwhile, the mass ratio of palladium to platinum is 1:0.5-2.0. The catalyst can be applied to catalytic hydrogenation for synthesis of benzotriazole ultraviolet absorbent. The preparation method of the catalyst is easy and convenient, the catalytic activity is high, the selectivity and yield of target products are high, good stability is achieved, and meanwhile three wastes generated in the hydrogenation process are fewer.

Description

(1) Technical field [0001] The invention relates to a carbon-supported multi-component catalyst and a preparation method thereof. The carbon-supported multi-component catalyst can be applied to catalytic hydrogenation to synthesize benzotriazole-type ultraviolet absorbers. (2) Background technology [0002] Benzotriazole UV absorbers are the main varieties of plastic light stabilizers. They have excellent UV absorption capacity and can absorb UV rays with a wavelength of 290-400nm. And it has the advantages of lighter color, lower toxicity, less volatilization, good oil resistance, good compatibility with polymers, etc., and is widely used in polypropylene, polyethylene, polyvinyl chloride, polyoxymethylene, poly Photochemical modification of various synthetic materials such as amide, polystyrene, polyurethane, alkyd resin, etc. [0003] The synthesis of benzotriazole UV absorbers is a complex multi-step reaction. Firstly, the azo intermediate corresponding to the product ...

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Problems solved by technology

However, when Raney nickel is used as a hydrogenation catalyst, the selectivity and yield of benzotriazole products are not high; moreover, Raney nickel is flammable, and there are potential safety hazards during use

It has also been reported that carbon-supported noble metals are used as hydrogenation catalysts to synthesize benzotriazole products. Compared with Raney nickel catalysts, carbon-supported noble metal catalysts are safer. For example: CIBAGEIGY (patent US5276161) uses 5% Pt / C Synthesis of UV-P by catalyst hydrogenation with a yield of 92%; patent US5104992 uses 5% Pd / C as catalyst to hydrogenate UV-320 with a yield of 87.3%; patent EP0794179A1 uses 4% Pd / C+1% Pt / C is a catalyst for the synthesis of UV-328. In this patent, adding hypophosphorous acid or sulfuric acid in the reducing system can improve the product yield, but it needs to add a large amount of liquid acid (the molar ratio of acid / raw material is 3.0) in the reaction system, which will produce relatively Too much waste acid pollutes the environment, and the liquid acid added at the same time tends to remain in the product, affecting product quality

[0016] It can be seen that the existing hydrogenation catalysts, whether they are Raney nickel catalysts or Pd / C, Pt / C catalysts, have defects such as low selectivity or the use of liquid acids.

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