A kind of method preparing 3-aminopropionitrile under supercritical condition

Abstract

The invention discloses a method for preparing 3-aminopropionitrile under a supercritical condition. According to the method, liquid ammonia and acrylonitrile are used as raw materials which are subjected to direct addition reaction in a pipeline reactor without adding a catalyst and a solvent to obtain 3-aminopropionitrile. The reaction according to the invention is carried out under a supercritical condition of the liquid ammonia, thus avoiding the use of a catalysts and a solvent when the liquid ammonia is used in reports in the past; a product can be obtained through continuous rectification; unreacted raw materials can be directly used; the process is safe and environmentally friendly, substances of non-reactive raw materials are not introduced, and the method accords with a concept of green chemistry. The conversion rate of acrylonitrile can reach 99.5-100.0%, and the selectivity can reach 85.5-95.8%, so that the acrylonitrile has a high industrial application value.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a method for preparing 3-aminopropionitrile under supercritical conditions. Background technique [0002] 3-aminopropionitrile, also known as β-aminopropionitrile (β-amino propionitrile, C 3 h 6 N 2 , Molecular Weight: 70.11, CAS No.: 151-18-8), colorless liquid, with ammonia odor, is an intermediate in the synthesis of alanine and pantothenic acid; 1,3-diaminopropane can be obtained by reduction; and phosgene The reaction can produce isocyanate, and the reaction with p-nitroaniline can produce a sweetener, which is also used as a pharmaceutical intermediate. [0003] The main synthetic method of 3-aminopropionitrile is obtained by the addition reaction of acrylonitrile and ammonia, and the reaction formula is as follows: [0004] CH 2 =CHCN+NH 3 →NH 2 CH 2 CH 2 CN [0005] The main by-product is that 3-aminopropionitrile continues to react with acrylonitrile to obtain 3,3...

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Problems solved by technology

[0020] In the above report, when synthesizing 3-aminopropionitrile, using alcohol as a solvent can reduce the amount of ammonia, speed up the reaction rate, and improve the selectivity of the main product. Nitrile is difficult to separate from the product, thus limiting its development in industry

The use of catalysts can effectively increase the product yield, but at the same time it also increases the cost. In the production process, the invalid catalyst needs to be replaced, which makes the operation complicated

To produce 3-aminopropionitrile by continuous reaction in a fixed-bed tubular reactor, it is necessary to recycle the by-product iminodipropionitrile and further react with ammonia to form the product, which makes the process complicated and consumes a lot of energy.

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