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Method for synthesizing hexanediamine by taking caprolactam as raw material

A technology of caprolactam and hexamethylenediamine, which is applied to the preparation of carboxylic acid amide, chemical instruments and methods, and the preparation of organic compounds, can solve the problems of undisclosed yield of hexamethylenediamine, low yield, difficult control, etc., and achieve The effect of easy equipment requirements, convenient post-processing, and mild reaction conditions

Active Publication Date: 2019-11-08
ZHENGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] There are very few reports on the synthesis of hexamethylenediamine from caprolactam. It was first reported in US2234566 and US2181140 patents that caprolactam reacted with ammonia gas under a dehydration catalyst and severe temperature to obtain 6-aminocapronitrile, and unreacted caprolactam was separated by distillation. Aminocapronitrile is synthesized into hexamethylenediamine by catalytic hydrogenation of aminocapronitrile subsequently on nickel or cobalt catalyst, but the yield of hexamethylenediamine is not disclosed in the patent; The method of caprolactam synthesis 6-aminocapronitrile reported in patent CN107739318A, CN107602416A and patent US2234566 The method of reporting is almost the same
Among them, the gas phase method reported by patent CN107602416A uses caprolactam to prepare 6-aminocapronitrile. The reaction temperature is about 350 ° C, and the contact time between caprolactam and ammonia is extremely short within 1 second, which is difficult to control; while the liquid phase method reported by patent CN107739318A Although the reaction temperature in the method of synthesizing 6-aminocapronitrile with caprolactam as a raw material is mild at about 280°C, its yield is not high, and its yield is about 50% analyzed from examples

Method used

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  • Method for synthesizing hexanediamine by taking caprolactam as raw material
  • Method for synthesizing hexanediamine by taking caprolactam as raw material
  • Method for synthesizing hexanediamine by taking caprolactam as raw material

Examples

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Embodiment 1

[0031] A kind of method taking caprolactam as raw material synthetic hexamethylenediamine comprises the following steps:

[0032] 1) Add 10g caprolactam into a 250ml single-mouth bottle, add 11g sodium hydroxide and 25ml water, reflux at 130°C for 3h and cool to room temperature to obtain 6-aminocaproic acid sodium salt; the molar ratio of caprolactam and sodium hydroxide is about is 1:3; the molar ratio of caprolactam to the amount of water added is 1:15.8;

[0033] 2) Then add 9ml of acetic anhydride (amino-protecting group, the amount of amino-protecting group is 1 times the equivalent of caprolactam) to the one-necked bottle of step 1), then after reaching 47°C, stir the reaction for 2 hours, then add concentrated hydrochloric acid to adjust The pH value of the solution is at 2, and the precipitated solid is recrystallized with water to obtain 6-acetylaminocaproic acid;

[0034] 3) Dry the product of step 2) to obtain 12g of solid; take 5g of the dried product and 0.15g o...

Embodiment 2

[0037] A kind of method taking caprolactam as raw material synthetic hexamethylenediamine comprises the following steps:

[0038] 1) Add 10g caprolactam into a 250ml single-mouth bottle, add 13g sodium tert-butoxide and 32ml water, reflux at 150°C for 2h and cool to room temperature to obtain 6-aminocaproic acid sodium salt; The ratio is about 1:1.5; the molar ratio of caprolactam to the amount of water added is 1:20;

[0039]2) Then slowly add 18ml of benzyl chloroformate (amino-protecting group, the amount of which is 1.5 times the equivalent of caprolactam) to the single-necked bottle of step 1), stir and react for 2 hours at room temperature, and then add to the reaction solution Extract the by-products in the reaction with 30ml of ether, repeat the operation twice, then add concentrated hydrochloric acid to the extracted aqueous layer solution under ice bath to adjust the pH to 5; put it in the refrigerator (minus 3°C) for 2h and filter to obtain a white solid N -Cbz-ami...

Embodiment 3

[0043] A kind of method taking caprolactam as raw material synthetic hexamethylenediamine comprises the following steps:

[0044] 1) Add 10g caprolactam into a 250ml single-necked bottle, add 7g sodium hydroxide and 16ml water, reflux at 100°C for 4h and cool to room temperature to obtain 6-aminocaproic acid sodium salt; the molar ratio of caprolactam and sodium hydroxide is about is 1:2; the molar ratio of caprolactam to the amount of water added is 1:10;

[0045] 2) Then slowly add 15ml of tetrahydrofuran and 20ml of benzyl chloride (amino-protecting group, the amount of amino-protecting group is twice the equivalent of caprolactam) to the single-necked bottle of step 1), reflux at 70°C for 10h, and cool to room temperature , adding concentrated hydrochloric acid to the obtained solution to adjust the pH value of the solution to 3; adding 20ml of ethyl acetate after the reaction to extract the product, and repeating the operation 3 times. The obtained ethyl acetate layer wa...

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Abstract

The invention discloses a method for synthesizing hexanediamine by taking caprolactam as a raw material. The method comprises the following steps that (1) after the hexanediamine, alkali and water aremixed, heating reflux is conducted, and thus 6-amino-caproate is obtained; (2) the 6-amino-hexanoate obtained in the step (1) is introduced into an amino protecting group to protect an amino end group, then acid is added for neutralization to generate aminocaproic acid with the amino protecting group; (3) after a product obtained in the step (2) is dried, a dehydration catalyst for amide is added, a heating reaction is conducted in the presence of an ammonia source to convert a carboxylic acid group into a cyano group, and thus product nitrile is obtained; and (4) after the product nitrile obtained in the step (3) is extracted and purified, catalytic hydrogenation is conducted to generate corresponding amine, then the protecting group is removed, and thus a target product can be obtained.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method for synthesizing hexamethylenediamine by using caprolactam as a raw material. Background technique [0002] Hexamethylenediamine is an important chemical raw material, which is often used to synthesize important industrial products such as nylon 66, nylon 610, HDI, etc. However, there is no production device for the synthesis of hexamethylenediamine adiponitrile in our country, and the need is completely dependent on imports , it is crucial to develop new synthetic methods. At present, there are not many methods for synthesizing hexamethylenediamine. In industry, the catalytic hydrogenation of adiponitrile is the main method, and the raw material adiponitrile is synthesized by butadiene and acrylonitrile. The production of adiponitrile by the butadiene method is further divided into the chlorination and cyanation of butadiene and the direct cyanat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/62C07C211/12
CPCC07C209/62C07C227/22C07C231/02C07C253/22C07C231/12C07C211/12C07C229/08C07C233/47C07C255/29C07C233/36Y02P20/55Y02P20/52
Inventor 赵清香王帅辉刘民英付鹏庞新厂崔喆赵海涛张晓朦赵蔚
Owner ZHENGZHOU UNIV
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