One process of using two fixed bed reactors to continuously catalyze the N-methyl-1,3-propyleneramine

Abstract

The invention discloses a process for preparing N-methyl-1,3-propylenediamine through continuous catalytic reaction in two fixed-bed reactors, which belongs to the technical field of organic chemical industry. Using monomethylamine and acrylonitrile as raw materials, first continuously pass through the first fixed-bed reactor to react to generate 3-methylaminopropionitrile intermediate, and then continuously enter the second fixed-bed hydrogenation reactor for catalytic hydrogenation Hydrogen to generate N-methyl-1, 3-propylenediamine, yield ≥ 99%. The process of the invention is continuous production, simple, less three wastes, energy saving, environmental protection, low cost, and easy to realize industrialization.

Description

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

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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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