Method for synthesizing hexamethylenediamine key intermediate

Abstract

The invention relates to a method for synthesizing a hexamethylenediamine key intermediate, and is particularly suitable for synthesizing a hexamethylenediamine key intermediate namely 6-aminocapronitrile. The method comprises the following steps of preheating caprolactam and ammonia water, respectively introducing the caprolactam and the ammonia water into a micro-channel reactor, and performingreaction; separating the material obtained after the reaction to obtain 6-aminocaproamide; and preheating and gasifying the 6-aminocaproamide obtained by separation, introducing the gasified 6-aminocaproamide into a reactor loaded with a catalyst, and performing a reaction to obtain the 6-aminocapronitrile. An existing process route is broken through, the hexamethylenediamine key intermediate namely the 6-aminocapronitrile is synthesized more efficiently by an innovative method, a 6-aminocaproamide intermediate is generated through caprolactam ring-opening hydrolysis, and then dehydrating is performed to generate the 6-aminocapronitrile, so that caprolactam polymerization is effectively reduced, catalyst surface coking is reduced, the utilization rate of raw materials is increased, the selectivity of products is improved, the service life of the catalyst is prolonged, the process flow is simple, the production cost is low, and the method is suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of organic chemical industry, in particular to a method for synthesizing a key intermediate of hexamethylenediamine, and is especially suitable for the synthesis of the key intermediate of hexamethylenediamine, 6-aminocapronitrile. Background technique [0002] Hexamethylenediamine is an important chemical raw material, mainly used in the production of nylon 66, nylon 610 and diisocyanate (HDI). At present, the method for producing hexamethylenediamine mainly includes the production method carried out through the intermediate adiponitrile and the production method carried out through the intermediate 6-aminocapronitrile, wherein, the method for producing hexamethylenediamine is carried out by preparing the intermediate adiponitrile The cost is high. In the method for producing hexamethylenediamine through the intermediate 6-aminocapronitrile, the direct ammoniation of caprolactam is mainly used to synthesiz...

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Problems solved by technology

[0004] patent CN201710942344.8 provides a method for preparing 6-aminocapronitrile by gas phase method, using caprolactam as raw material, and caprolactam steam and hot ammonia gas in a certain mass ratio Mixing; the obtained mixture of caprolactam vapor and hot ammonia gas is subjected to ammoniation dehydration reaction in the presence of a catalyst to obtain an ammoniated effluent; the obtained ammoniated effluent is separated and purified to obtain pure 6-amino Capronitrile: In this method, caprolactam is dehydrated in the reaction process to generate 6-aminocapronitrile, and a small amount of water promotes the polymerization of caprolactam at high temperature, while the polymer produced by caprolactam polymerization will coke and adhere to the surface of the catalyst, reducing catalyst activity and service life. Affect the normal operation of the reaction device, thereby affecting the response efficiency of the whole set of questions

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