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

A one-step, catalytic hydrogenation technology of nitrobenzene, which is applied in the preparation of amino compounds, chemical instruments and methods, and the preparation of organic compounds, can solve the problems of high reaction pressure and temperature, complex process routes, and large total reaction losses, and achieve Relaxed equipment requirements, simplified process flow, and reduced environmental pollution

Active Publication Date: 2013-12-18
XIANGTAN UNIV
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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

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add 1.23g of nitrobenzene, 0.25g of catalyst (5%Pd / CNTs), and 20ml of isopropanol as a solvent into the autoclave, connect the autoclave to the hydrogen cylinder, check the airtightness, inject hydrogen to evacuate, repeat five times, To exhaust other gases as much as possible, and then react for 4 hours in an oil bath at 120°C under a hydrogen pressure of 3Mpa. The mixture after the reaction was filtered, and the filtrate was analyzed by gas chromatography using the internal standard method. The conversion rate of nitrobenzene was calculated to be 100%, the selectivity of cyclohexylamine was 21.53%, and the selectivity of dicyclohexylamine was 69.28%. .

Embodiment 2

[0027] Add 1.23g of nitrobenzene, 0.25g of catalyst (5%Pd / CNTs), and 20ml of isopropanol as a solvent into the autoclave, connect the autoclave to the hydrogen cylinder, check the airtightness, inject hydrogen to evacuate, repeat five times, To exhaust other gases as much as possible, and then react for 4 hours in an oil bath at 140°C under a hydrogen pressure of 3Mpa. The mixture after the reaction is filtered, and the filtrate is analyzed by gas chromatography using the internal standard method. The calculated conversion rate of nitrobenzene is 100%, the selectivity of cyclohexylamine is 20.32%, and the selectivity of dicyclohexylamine is 77.2%. .

Embodiment 3

[0029] Add 1.23g of nitrobenzene, 0.25g of catalyst (5%Pd / CNTs), and 10ml of isopropanol as a solvent into the autoclave, connect the autoclave to the hydrogen cylinder, check the airtightness, inject hydrogen to evacuate, repeat five times, To exhaust other gases as much as possible, and then react for 4 hours in an oil bath at 120°C under a hydrogen pressure of 3Mpa. The mixture after the reaction is filtered, and the filtrate is analyzed by gas chromatography using the internal standard method. The calculated conversion rate of nitrobenzene is 100%, the selectivity of cyclohexylamine is 18.53%, and the selectivity of dicyclohexylamine is 72.96%. .

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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...

Claims

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Application Information

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IPC IPC(8): C07C211/35C07C209/36
Inventor 刘平乐耿晶晶罗和安郝芳游奎一
Owner XIANGTAN UNIV
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