A kind of carbon supported multi-component catalyst and its preparation method and application

Abstract

The invention provides a carbon-supported multi-component catalyst and a preparation method thereof. The catalyst is composed of a carrier and a metal active component loaded on the carrier, the carrier is activated carbon, and the metal active component is palladium and platinum. and a transition metal additive; based on the quality of the carrier activated carbon, the palladium loading is 0.5wt% to 5.0wt%, the platinum loading is 0.5wt% to 5.0wt%, and the transition metal additive loading is 0.1wt% ~2.5wt%; Simultaneously, the mass ratio of palladium and platinum is 1:0.5~2.0; Catalyst of the present invention can be used in catalytic hydrogenation synthesis benzotriazole ultraviolet absorber; High activity, high selectivity and yield of the target product, good stability, and less waste generated during the hydrogenation process.

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: CIBA GEIGY (patent US5276161) uses 5% Pt / C is the catalyst to catalyze hydrogenation to synthesize UV-P with a yield of 92%; patent US5104992 uses 5% Pd / C as a catalyst to hydrogenate UV-320 with a yield of 87.3%; patent EP0794179A1 uses 4% Pd / C+1% Pt / C is the catalyst for synthesizing UV-328. This patent can increase the product yield by adding hypophosphorous acid or sulfuric acid in the reduction system, 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 A lot of waste acid will pollute the environment, and the liquid acid added at the same time is likely 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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