Method for preparing cyclohexylamine and dicyclohexylamine from nitrobenzene through one-step catalytic hydrogenation

Abstract

The invention relates to a method for preparing cyclohexylamine and dicyclohexylamine from nitrobenzene through one-step catalytic hydrogenation, belonging to the technical field of organic catalysis. The method comprises the steps: with the nitrobenzene and hydrogen as raw materials, adding a solvent, the nitrobenzene and a catalyst into a reaction kettle, and controlling the reaction pressure at 0.5-4Mpa, the reaction temperature at 60-160 DEG C and the reaction time within 2-8h to obtain the cyclohexylamine and the dicyclohexylamine, wherein the adopted catalyst is a Pd / CNTs catalyst or Pd-Ni / CNTs catalyst. According to the invention, the cyclohexylamine and the dicyclohexylamine are synthesized by using the nitrobenzene at one step, so that the reaction loss is reduced, the utilization ratios of the raw materials are increased, the emission of various waste reaction liquids can be reduced, and the cost for treating waste liquid can be reduced. The method has the advantages of greenness, economy, safety, simplicity and convenience in operation, few equipment requirements and the like so as to be suitable for industrial production.

Description

technical field [0001] The invention relates to a method for preparing cyclohexylamine and dicyclohexylamine by one-step catalytic hydrogenation of nitrobenzene, which belongs to the technical field of organic catalysis. Background technique [0002] Cyclohexylamine compounds (cyclohexylamine, dicyclohexylamine) are organic chemical intermediates with a wide range of uses and important raw materials for the organic synthesis industry. Among them, cyclohexylamine is widely used in papermaking, rubber additives, anti-corrosion In recent years, with the continuous development of rubber and textile industries, and the expansion of industrial demand for cyclamate, the demand for cyclohexylamine has also continued to increase. People have paid more and more attention to the synthesis process of cyclohexylamine and conducted extensive research. [0003] The traditional synthesis of cyclohexylamine mainly adopts aniline normal pressure hydrogenation method and pressurized hydrogena...

AI Technical Summary

Problems solved by technology

The nitrobenzene iron powder reduction method is characterized by good product quality and high selectivity, but since the iron powder reduction generally needs to be carried out in an acidic medium, a certain amount of alkali needs to be added to neutralize the acid after the reaction, so the production The process will produce a large amount of salty wastewater and waste residue, causing serious environmental pollution problems

[0004] The above-mentioned process route of synthesizing cyclohexylamine by the two-step method of nitrobenzene is complex, the total loss of reaction is relatively large, and the utilization rate of raw material nitrobenzene is not high, therefore, the exploration of the process route for preparing cyclohexylamine in one step from nitrobenzene is of great significance significance and value

[0005] At present, there are relatively few studies on the preparation of cyclohexylamine and dicyclohexylamine by one-step hydrogenation of nitrobenzene at home and abroad, and various methods have reaction pressure (the reaction pressure is generally 14.7-19.6Mpa), and the temperature is too high (the highest temperature reached about 240°C), the reaction time is too long (the reaction time is generally about 16h), the reaction conditions are harsh, the cost is high, the yield of cyclohexylamine is too low (the conversion rate is generally about 7%-30%), etc. question