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Preparation method of hexamethylenediamine

A technology of hexamethylenediamine and adiponitrile, which is applied in the field of preparation of hexamethylenediamine, can solve problems such as reduction, low efficiency, and activity decline, and achieve the effects of good stability, reduced post-processing energy consumption, and reduced catalyst cost

Pending Publication Date: 2022-03-29
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method does not use ethanol as a solvent, thus avoiding the generation of N-ethylhexamethylenediamine, but in order to maintain the activity of the catalyst, the reaction needs to be carried out at an extremely low space velocity, the residence time is as long as 10h, and the efficiency is low
However, the activity of the catalyst decreased significantly after a period of reaction
In addition, the patent does not mention the method of reducing the content of 1,2-cyclohexanediamine

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] First add 6g Raney cobalt catalyst (A=298.7ml / min g cat ), 200g ethanol solvent, 3.5g 15% LiOH·H 2O water solution, 8.8 g deionized water. Then replace with nitrogen and hydrogen respectively three times, and pressurize the hydrogen to 3MPa. Turn on the stirring, the stirring rate is 800rpm, and the temperature is raised. When the reaction temperature rises to 90° C., open the hydrogen valve and keep the hydrogen outlet pressure reducing valve at 5 MPa. Open the adiponitrile feed pump at 0.4g / g cat Adiponitrile was poured into the reaction kettle at a flow rate of min. During the reaction, the temperature was maintained at 90° C. and the pressure was 5 MPa. A total of 200 g of adiponitrile was fed. After the feed is complete, when the instantaneous hydrogen absorption rate drops to 0, the reaction is stopped, the temperature is lowered, filtered, and a sample is taken for analysis.

[0041] It took a total of 90 minutes from the start of feeding to the stop of the ...

Embodiment 2

[0043] First add 12g Raney cobalt catalyst (A=348.9ml / min·g cat ), 200g ethanol solvent, 9.8g 15% LiOH·H 2 O water solution, 11.0 g deionized water. Then replace with nitrogen and hydrogen respectively three times, and pressurize the hydrogen to 3MPa. Turn on the stirring, the stirring rate is 800rpm, and the temperature is raised. When the reaction temperature rises to 95° C., open the hydrogen valve and keep the hydrogen outlet pressure reducing valve at 4 MPa. Open the adiponitrile feed pump, at 0.8g / g cat Adiponitrile was poured into the reaction kettle at a flow rate of 1 min. During the reaction, the temperature was maintained at 95° C., the pressure was 4 MPa, and a total of 300 g of adiponitrile was fed. After the feed is complete, when the instantaneous hydrogen absorption rate drops to 0, the reaction is stopped, the temperature is lowered, filtered, and a sample is taken for analysis.

[0044] It took a total of 40 minutes from the start of feeding to the stop ...

Embodiment 3

[0046] First add 5g Raney cobalt catalyst (A=251.3ml / min·g cat ), 200g ethanol solvent, 1.2g 15% LiOH·H 2 O water solution, 4.9 g deionized water. Then replace with nitrogen and hydrogen respectively three times, and pressurize the hydrogen to 3MPa. Turn on the stirring, the stirring rate is 800rpm, and the temperature is raised. When the reaction temperature rises to 100° C., open the hydrogen valve and keep the hydrogen outlet pressure reducing valve at 6 MPa. Open the adiponitrile feed pump at 0.2g / g cat Adiponitrile was pumped into the reaction kettle at a flow rate of min. During the reaction, the temperature was maintained at 100° C., the pressure was 6 MPa, and a total of 100 g of adiponitrile was fed. After the feed is complete, when the instantaneous hydrogen absorption rate drops to 0, the reaction is stopped, the temperature is lowered, filtered, and a sample is taken for analysis.

[0047] It took a total of 108 minutes from the start of feeding to the stop of...

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PUM

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Abstract

The invention provides a preparation method of hexamethylenediamine, which comprises the following steps: adding a solvent, a catalyst, a cocatalyst and water into a reactor, continuously adding adiponitrile into the reactor at a certain temperature and hydrogen pressure, and carrying out hydrogenation reaction to generate hexamethylenediamine, the catalyst is a Raney cobalt catalyst, and the activity of the catalyst is expressed as 250-350 ml / min.gcat by the initial hydrogen absorption rate of the reaction. According to the method disclosed by the invention, the reaction can be carried out at a relatively low catalyst concentration, the yields of impurities 1, 2-cyclohexanediamine and N-ethyl hexamethylenediamine which are difficult to separate in the reaction liquid are both lower than 0.1%, the yield of hexamethylenediamine is higher than 99.0%, and the yield of 1, 2-cyclohexanediamine and N-ethyl hexamethylenediamine is higher than 99.0%. The unit consumption of the catalyst and the energy consumption in the post-treatment process are effectively reduced, and the production cost is reduced.

Description

technical field [0001] The invention relates to a preparation method of hexamethylenediamine, which belongs to the technical field of organic catalysis. Background technique [0002] Hexamethylenediamine is an important chemical raw material, mainly used in the production of nylon 66, nylon 610 and HDI (1,6-hexamethylene diisocyanate). The production technology of hexamethylenediamine mainly includes adiponitrile method, hexanediol method, caprolactam method, butadiene method, etc., but the methods for large-scale production of hexamethylenediamine are all the adiponitrile method. The adiponitrile method is divided into high-pressure method and low-pressure method. The high-pressure method uses an iron catalyst, the reaction temperature is 100-180°C, the pressure is 30-35MPa, and the selectivity of hexamethylenediamine is about 90%-95%. The low-pressure method adopts Raney catalyst, the reaction temperature is 60-100°C, and the pressure is 1.8-3MPa. Compared with the high-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/48C07C211/12
CPCC07C209/48B01J25/02C07C211/12
Inventor 张立娟张聪颖刘帅王静王宏李盼李兴华
Owner WANHUA CHEM GRP CO LTD
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