A kind of method for preparing 2-amino-5-naphthol-7-sulfonic acid

Abstract

The method discloses a method for preparing 2-amino-5-naphthol-7-sulfonic acid, and the method is implemented by using the following system. The system comprises a first synthesis reaction tower, a second synthesis reaction tower, a hydrolysis reaction tower, an adjustment reaction tower, a dissolution reaction tower, a suction filtration reaction tower, a concentration reaction tower, a third synthesis reaction tower, an acidification reaction tower, a centrifugation reaction tower, a drying reaction tower, a finished product storage tank, a wastewater treatment system, a tobias acid liquid storage tank, a sulfur trioxide gas storage tank, a concentrated sulfuric acid liquid storage tank, a sodium hydroxide solid storage tank, a hydrochloric acid liquid storage tank, and a pure water storage tank. The 2-amino-5-naphthol-7-sulfonic acid product prepared by the method disclosed by the invention has high purity which is greater than 92.8%, the moisture content is less than 1%, the crystallization rate is less than 0.5%, and the free acid is less than 5%.

Description

technical field [0001] The invention relates to a method for preparing 2-amino-5-naphthol-7-sulfonic acid, which belongs to the field of chemical industry. Background technique [0002] J acid is an azo dye intermediate used in the production of wool, silk and cotton dyeing. Since the industrial production, along with the development of the dye industry, great progress has been made in J acid production technology, production scale and application range at home and abroad. The chemical name of J acid is 2-amino-5-naphthol-7-sulfonic acid. Its dry product is off-white powder. It has low solubility in water and is easily soluble in alkali to make corresponding salt. Its sodium salt solution has blue fluorescence . The chlorine-containing compound of J acid is a yellow needle-like crystal, soluble in water, and can be self-coupled into a purple dye in a sodium carbonate solution. This product is mainly used in the preparation of direct dyes, reactive dyes, etc. [0003] At ...

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Problems solved by technology

[0003] At present, most of the traditional methods are used to prepare J acid in China. The product has many impurities and low yield, and discharges a large amount of high-concentration waste acid, which is difficult to treat and seriously pollutes the environment.

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