Method for refining 4-amino diphenylamine

Abstract

The present invention relates to a method for refining 4-aminodiphenylamine by adopting three-column continuous rectification and intermittent distillation. The crude product of 4-aminodiphenylamine can be obtained by rectification in the column No.1, and the substances of phenylamine, phenazine and azobenzene can be obtained at the top of column, said crude product can be purified in column No.2, in the column No.3 the phenylamine is separated, and the intermittent column can be used for making batch distillation of 4-aminophenylamine made up by using column bottoms of column No.2 and returning it into column No.2 for refining it. The yield rate of its whole process can be raised to 99% from 94%, and the content of 4-aminodiphenylamine in the finished product is greater than 99 wt%, at the same time the phenylamine can be recovered, and can be used.

Description

technical field

[0001] The invention relates to a method for purifying 4-aminodiphenylamine, in particular to a method for purifying 4-aminodiphenylamine by three-column rectification and batch distillation. Background technique

[0002] 4-Aminodiphenylamine is an important intermediate compound of rubber antioxidants, and its quality directly affects the quality of downstream products. The existing method of distilling 4-aminodiphenylamine generally adopts simple distillation, its vacuum degree is 0.095MPa, the kettle temperature is 280℃-330℃, the top temperature is 220℃-240℃, and the heating adopts flue gas heating or far-infrared heating. Heating, using this method in the later stage of simple distillation, the kettle temperature is as high as 300 ℃ or more, and a large amount of coking is formed in the kettle at the same time, resulting in a decrease in the product yield and quality of 4-aminodiphenylamine; at the same time, simple distillation is used. The number of pl...

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