Preparation method and application of a carbon nanotube-supported quaternary amorphous nickel-based catalyst

Abstract

The invention discloses a preparation method for a carbon nanotube loaded quaternary amorphous nickel-based catalyst and application. According to the preparation method, a multi-metal doped multi-wall carbon nanotube loaded quaternary amorphous nickel-based catalyst is prepared by using a chemical reduction method, that is, MgO-Cu-Ni-X / MWCNT, wherein X=B or P. Due to introduction of Cu, the reducing capacity of a Ni precursor is effectively reduced, dispersion of metallic Ni nanoparticles on the surfaces of carbon nanotubes is promoted, and besides due to metallic synergism of Cu and Ni, a relatively large amount of Ni<0+> can be formed. Due to introduction of Mg, a great amount of alkali sites can be provided for the surface of the catalyst, and due to formation of a NiO-MgO hybrid, excessive hydrogenation of reactants is inhibited, and excessive byproducts can be avoided. Due to a unique mesoporous structure of the multi-wall carbon nanotubes as a carrier, and mutual action of the multi-wall carbon nanotubes and active components, the hydrogenation activity of the catalyst is greatly improved, and a relatively high conversion rate and total product selectivity can be achieved when the catalyst is applied to an adiponitrile hydrogenation reaction.

Description

technical field [0001] The invention relates to the field of material preparation, in particular to a preparation method and application of a carbon nanotube-loaded quaternary amorphous nickel-based catalyst. Background technique [0002] The hydrogenation of adiponitrile mainly produces 6-aminocapronitrile and hexamethylenediamine, wherein 6-aminocapronitrile is a very critical step in the new process of butadiene / adiponitrile synthesis of caprolactam. In the butadiene / adiponitrile process, the research on the hydrocyanation process of butadiene based on nickel phosphine homogeneous catalyst in the first step has been relatively mature. DuPont was the first to use this method to produce adiponitrile. Through the two-step reaction of butadiene hydrogenation and then cyanation, the yield of adiponitrile can reach 95.6%. For the research on the process of cyclization of 6-aminocapronitrile to caprolactam in the third step, companies such as BASF and DSM have applied for relat...

AI Technical Summary

Problems solved by technology

However, the recovery rate of the catalyst is low, and a large amount of alkali is required to suppress the formation of by-products

[0009] In summary, the above catalysts for the hydrogenation of adiponitrile all have problems to a certain extent, or are difficult to separate and lead to recycling difficulties; or use a large amount of precious metals As an active component, it causes resource waste and high cost; or the activity of the catalyst is not very high; or the reaction conditions are very demanding

For example, Raney type catalysts, metal rhodium-based catalysts and other precious metal catalysts have high cost, low recycling rate, and are easy to deactivate. At the same time, due to the large amount of alkaline water (ammonia) used, the equipment is severely corroded, the amount of wastewater treatment is large, and the reaction pressure is very high. High, further increasing the production cost, the economic benefit is not significant; another example is the amorphous alloy catalyst, the hydrogen consumption in the gas phase method is extremely high, and the reaction temperature is high, resulting in higher production costs and more complicated processes