Preparation method and application of nitrogen-doped activated carbon supported alkali metal modified nickel-based catalyst

Abstract

The invention discloses a preparation method and application of a nitrogen-doped activated carbon supported alkali metal modified nickel-based catalyst. The preparation method includes the steps that firstly, acid activation or acid modification is conducted on a wooden charcoal material, nitrogen doping treatment is conducted on the wooden charcoal material, and then the wooden charcoal material is impregnated and supported with nickel and alkali metals. The nitrogen-doped activated carbon supported alkali metal modified nickel-based catalyst is applied to an adiponitrile hydrogenation process and can have high activity and high overall selectivity on 6-aminocapronitrile and hexamethylenediamine under relatively mild reaction conditions. Usage of a large number of precious metals serving as active components is avoided, equipment is not corroded (a large amount of additional ammonia or alkali metal hydroxide for inhibiting the formation of by-products is not needed), the cost is low, the catalyst is friendly to the environment, the preparation process of the catalyst is simple, the used active charcoal material is cheap and easy to obtain, and the preparation method is simple and has a very good application prospect.

Description

technical field [0001] The invention relates to the fields of material preparation and chemical engineering, in particular to a preparation method and application of a nitrogen-doped activated carbon-supported alkali metal-modified nickel-based catalyst. Background technique [0002] The hydrogenation of adiponitrile mainly produces 6-aminocapronitrile and hexamethylenediamine, and 6-aminocapronitrile is cyclized to synthesize caprolactam. Caprolactam is one of the important organic chemical raw materials, mainly used to synthesize nylon-6 fiber and nylon-6 engineering plastics . Due to its excellent thermal stability, high mechanical strength, chemical resistance and processability, caprolactam has a wide range of applications and is mainly used in automobiles, medical equipment, ships, electrical and electronic, daily necessities and other fields. From a global perspective, the consumption areas of caprolactam mainly include three categories of fibers (civilian silk, indu...

AI Technical Summary

Problems solved by technology

[0011] Rh / α-Al prepared by ion exchange method by Alini et al. 2 o 3 The catalyst is used in the liquid-phase partial hydrogenation of adiponitrile. Under the reaction conditions of 3 MPa hydrogen pressure, 500 psi ammonia pressure, and 100°C, when the conversion rate of adiponitrile is 60%, the selectivity of aminocapronitrile It can reach 99%, but the recycling rate of precious metal catalysts is low, and it is easy to deactivate. At the same time, it is necessary to add a large amount of ammonia or alkali metal hydroxide to inhibit the formation of by-products

[0012] To sum up, the above catalysts for the hydrogenation of adiponitrile either have complex preparation processes, or use a large amount of noble metals as active components, or are not very active, which makes the cost higher

Raney-type catalysts, metal rhodium-based catalysts and other noble metal catalysts have high costs. At the same time, due to the large amount of alkaline water (ammonia) used, the equipment is severely corroded, the amount of wastewater to be treated is large, and the reaction pressure is high, which further increases the production cost. Insignificant; the amorphous alloy catalyst consumes a lot of hydrogen in the gas phase method and the reaction temperature is very high, which leads to higher production cost and more complicated process; and the precious metal rhodium-based catalyst has a low recycling rate and is also prone to failure. active, but also need to add a large amount of ammonia or alkali metal hydroxide to inhibit the formation of by-products