Refining process of long-carbon-chain dinitrile

Abstract

The invention belongs to the technical field of fine chemical products, and particularly relates to a refining process of long-carbon-chain dinitrile. According to the present invention, the long carbon chain dinitrile and the ethanol are proportionally added into the evaporative crystallizer, the temperature of the dinitrile solution is reduced through the ethanol evaporation so as to form the supersaturated solution so as to crystallize, and the mother solution is separated so as to finally obtain the refined product, and compared with the traditional cooling crystallization refining process, the vacuum concentration cooling crystallization process is adopted, such that the operation is simple and convenient, and the production cost is low. The supersaturation degree of crystal slurry is uniform, the particle size distribution is good, the vessel wall is not scaled, the energy consumption is low, no pollution is caused, and the product purity is high.

Description

technical field [0001] The invention belongs to the technical field of fine chemical products, and in particular relates to a process for refining long carbon chain binary nitriles. Background technique [0002] Long carbon chain dibasic nitrile is the pre-intermediate of hydrogenation synthesis of long carbon chain dibasic amine, and long carbon chain dibasic amine is the main raw material for synthesizing polyamide, and the preparation of polyamide requires relatively high purity of raw materials, so, In order to obtain high-quality long carbon chain diamines, there must be certain requirements for the purity of long carbon chain dibasic nitriles. [0003] Normally, the long carbon chain dibasic nitrile is prepared by ammonification reaction using long carbon chain dibasic acid and liquid ammonia as raw materials, but because the long carbon chain dibasic acid contains a certain proportion of homologues, it The long carbon chain dibasic nitrile contains the dibasic nitril...

AI Technical Summary

Problems solved by technology

[0005] One, the traditional rectification method, the main defect that this method exists is: 1) equipment is many, process control requirement is high; 2) product can reach higher purity, if reach high purity, specific energy consumption is big; 3) ammoniation intermediate The body is easy to coke during the rectification process, which not only affects the yield, but also affects the normal operation of the rectification tower

[0006] 2. The cooling crystallization process of the crystallizer is used, and the disadvantages of this method are also obvious: 1) The wall of the crystallizer is easy to scar as a heat exchange surface; 2) Both cooling water is used to cool down and the solvent must be recovered, so the energy consumption is high; 3) The crystals are separated by a centrifuge, and the workload is large; 4) The solvent volatilizes, which is neither safe nor environmentally friendly

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