Process for preparing N-methyl-1,3-propane diamine through continuous catalytic reaction by using two fixed bed reactors

Abstract

The invention discloses a process for preparing N-methyl-1,3-propane diamine through continuous catalytic reaction by using two fixed bed reactors, belonging to the technical field of organic chemical industry. According to the invention, monomethylamine and acrylonitrile are used as raw materials, a 3-methylaminopropionitrile intermediate is generated through continuous reaction in a first fixed bed reactor, and then the intermediate continuously enters a second fixed bed hydrogenation reactor for catalytic hydrogenation, so N-methyl-1,3-propane diamine is generated, and the yield is larger than or equal to 99%. The process disclosed by the invention is continuous in production, simple in process, less in three wastes, reduced in energy consumption, friendly to environment, low in cost and easy to industrialize.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry and relates to a process for continuously preparing N-methyl-1,3-propanediamine. Background technique [0002] N-methyl-1,3-propanediamine belongs to lower aliphatic diamine and is an important organic chemical intermediate, widely used in medicine, feed, food and other fields. [0003] There are two main synthetic routes of N-methyl-1,3-propanediamine, the first is to use acrylonitrile and monomethylamine as raw materials to prepare N-methyl-1,3-propanediamine, which is At present, the mainstream synthetic route of the industry, wherein the present invention adopts this synthetic route; the other is to use 1,3-propanediamine and methanol as raw materials, and methylation reaction occurs to prepare N-methyl-1,3-propanediamine, Although the technological process is simple, the products obtained from this reaction are mostly mixtures of secondary and tertiary amines, which have ma...

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Problems solved by technology

[0003] There are two main synthetic routes of N-methyl-1,3-propanediamine, the first is to use acrylonitrile and monomethylamine as raw materials to prepare N-methyl-1,3-propanediamine, which is At present, the mainstream synthetic route of the industry, wherein the present invention adopts this synthetic route; the other is to use 1,3-propanediamine and methanol as raw materials, and methylation reaction occurs to prepare N-methyl-1,3-propanediamine, Although the process flow is simple, the products obtained from this reaction are mostly mixtures of secondary and tertiary amines, which have many by-products and the disadvantages of difficult product separation, making it difficult to realize large-scale industrial applications.

[0004] The first method takes acrylonitrile and monomethylamine as raw material reaction to generate 3-methylaminopropionitrile, and then obtains N-methyl-1,3-propanediamine by hydrogenation reduction of 3-methylaminopropionitrile, the method route Simple and direct, the reaction conversion rate is high, but most domestic factories currently use batch reactor reaction equipment, so that the intermediate 3-methylaminopropionitrile and the product N-methyl-1,3-propanediamine are often reacted Deterioration occurs during the process, resulting in a low yield of the final product and complex distillation and purification of the product

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