Preparation method of heavy-metal-free dye

Abstract

The invention relates to a preparation method of a heavy-metal-free dye. The method comprises the following steps: 4-tert-amyl-2-amino-6-nitrophenol is added to a sodium hydroxide solution, sodium nitrite is added, and a solution A is obtained; the solution A is added dropwise to water, ice and hydrochloric acid, and a diazonium salt is obtained; 1,3,5-pyrazolone is dissolved in sodium carbonate and sodium hydroxide, a coupled liquid is obtained, the diazonium salt is added to the coupled liquid for reaction, and an azo dye is obtained; basic chromium sulphate is dissolved in water, a salicylic acid solution after dissolution with sodium hydroxide is added, and a chromaking agent is prepared; the azo dye and the chromaking agent are mixed, pH is regulated to 10-11, disappearance of the azo dye is taken as a reaction endpoint, a reaction liquid is cooled to 65-70 DEG C, the dye is precipitated, cooled to the temperature lower than 45 DEG C, filtered, washed and dried, and the heavy-metal-free dye can be obtained. The dye prepared with the preparation method is free of heavy metal, has little harm to a human body and can reduce environmental pollution.

Description

technical field

[0001] The invention relates to a dye, in particular to a preparation method of a heavy metal-free dye. Background technique

[0002] At present, dyes are widely used and are an indispensable part of modern life. However, the dyes produced by the old dyeing technology all contain heavy metals. When used, they cause great harm to people and also cause great environmental pollution.

[0003] Therefore it is necessary to design a kind of preparation method without heavy metal dyes, to overcome the above-mentioned problems. Contents of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing heavy metal-free dyes. The prepared heavy metal-free dyes are less harmful to humans and can reduce environmental pollution.

[0005] The present invention is achieved like this:

[0006] The invention provides a kind of preparation method of heavy metal-free dye, comprises the following st...