Continuous prepn. of amine

Abstract

Disclosed is a process for the preparation of amines by continuously feeding a carboxamide, aqueous alkaline hypohalite, and aqueous alkaline hydroxide to a first reaction zone to form a N-halocarboxamide, measuring the concentration of at least one reaction component in the effluent from the first reaction zone, and using the result of that measurement to control the feed rate of at least one of the feed components of to achieve at least 90% conversion of the carboxamide in the first reaction zone. The effluent from the first reaction zone is fed continuously to a second reaction zone where it further reacts to form an aqueous solution of an amine. The effluent from the second reaction zone may be fed continuously to a distillation column. The process is particularly useful for the preparation of cyclopropylamine.

Description

technical field [0001] The present invention relates to a process for the preparation of amines. More particularly, the present invention relates to a continuous process for the preparation of amines by the reaction of basic hypohalites with carboxamides. Background technique [0002] Amines are important intermediates for the preparation of liquid crystal polymers, agrochemicals, and pharmaceutical compounds. Although many simple aliphatic and aromatic amines are accessible by efficient, low-cost methods such as reductive amination, displacement of halides with ammonia, or amination of alcohols, many are synthetically difficult, sterically hindered, or More reactive amines are prepared from their corresponding carboxamides by Hofmann reactions. These more complex amines are particularly useful in the production of agrochemical and pharmaceutical compounds. For example, cyclopropylamine is particularly useful as an agrochemical and pharmaceutical intermediate, and is prod...

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Problems solved by technology

[0008] As can be seen from the above methods, the known preparation of amines via the Hofmann reaction requires several complex process steps in order to avoid side reactions

These methods are difficult to perform in a continuous fashion and thus operate with low space-time yields

Among the known continuous methods, no method for manipulating the Hofmann reaction in a selective manner generally applicable to a wide variety of carboxamides has been provided.

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