Preparation methods of nitrile and corresponding amine

Abstract

The invention relates to a preparation method of nitrile. Compared with the prior art, the preparation method has the characteristics of obvious reduction of the usage amount of ammonia sources, low environmental pressure, low energy consumption, low production cost, high purity and yields of nitrile products, and the like, and can be used for obtaining nitrile with a more complex structure. The invention also relates to a method for preparing corresponding amine with nitrile.

Description

Technical field [0001] The invention relates to a method for producing a nitrile and a method for producing corresponding amines from the nitrile. Background technique [0002] Aromatic polynitriles such as aromatic dibasic nitriles are fine chemical intermediates with a wide range of uses. Using the chemical activity of their cyano groups, they can be used to synthesize a series of pesticides, medicines, dyes, perfumes, etc., which are widely used in various aspects of the national economy. field. [0003] The traditional preparation methods of aromatic dibasic nitriles include sandmeyer reaction, direct cyanidation of halogenated hydrocarbons and cyanide, dehydration of aromatic aldehydes by aldoxime or gas-phase catalytic ammoniation, etc. These methods generally have long reaction routes, complex processes, and difficult separation and purification. , The pollution is serious, especially the raw materials are difficult to obtain or need to use more expensive reagents, so the p...

AI Technical Summary

Problems solved by technology

[0003] The traditional preparation methods of aromatic dibasic nitriles include sandmeyer reaction, direct cyanation of halogenated hydrocarbons and cyanides, dehydration of aromatic aldehydes through aldoxime or gas-phase catalytic ammoniation, etc. These methods generally have long reaction routes, complicated processes, and difficult separation and purification. , serious pollution, especially raw materials are difficult to obtain or more expensive reagents need to be used, so the production cost is high, and it is not suitable for industrial production

[0004] At present, the main method used in the production of aromatic dibasic nitriles is aromatic hydrocarbon ammoxidation technology. Compared with the traditional method, the ammoxidation method has the advantages of cheap and easy-to-obtain raw materials, short reaction routes, and easy-to-handle products, but there are still The following four serious problems: (1) in order to improve the yield, NH3 consumption is too large; (2) a large amount of waste ammonia water is produced in the reaction process, which causes great pressure to the environment and post-treatment; (3) the scope of the reaction substrate Narrow, low selectivity when preparing alkyl mononitriles; (4) high reaction temperature (above 410°C), high requirements for catalyst preparation

[0006] But, the inventor of the present invention finds by research, and prior art is when producing corresponding aliphatic polyhydric nitrile by aliphatic polycarboxylic acid ammoniation method, in order to make ammoniation reaction fully carry out, this technology must be in the whole carboxylic acid During the ammoniation process or during a long reaction time, the ammonia source (ammonia gas) is continuously supplied (introduced) into the reaction system as a raw material, so the amount of ammonia gas is huge, resulting in the actual amount of ammonia gas far exceeding the ammoniation reaction. The amount used may be tens of millions of times the actual reaction requirement, resulting in extremely low utilization of ammonia gas

In addition, due to the extremely low utilization rate of ammonia, the ammonification reaction produces a large amount of waste ammonia water but cannot be recycled. After discharge, it will cause huge pressure on the environment, which is inconsistent with the current green production concept.

Moreover, since the ammoniation reaction of this technology adopts an overall higher reaction temperature (for example, exceeding 300° C.) and an overall longer reaction time, the energy consumption is higher, resulting in higher production costs, and there are also reactions during the reaction process. Severe material loss (for example, the reaction material is entrained out of the reaction system due to the continuous feeding of ammonia gas flow) and many side reactions, which make it difficult to effectively improve the quality and yield of nitrile products, etc.

Images