A kind of method for preparing 1-amino-4-naphthalene sulfonate sodium

Abstract

The invention discloses a method for preparing sodium 1-amino-4-naphthalene sulfonate, comprising: (1) Reductive sulfonation reaction: adding water, an organic solvent, 1-nitronaphthalene, and reducing sulfonation to a reactor in sequence Heat up to 108-114°C for reflux reaction, and react for 6-9h to the end of the reaction; (2) cooling desalination: cool the material obtained in step (1) to 0-10°C to precipitate inorganic salts, then suction filter or press Filtrate, collect filtrate 1; (3) material acidification: the filtrate 1 collected in step (2) is added in the reactor, add sulfuric acid to adjust filtrate pH=1-2, be warming up to 50-60 ℃, then suction filtration or pressure filtration, Collect filter cake 2 and filtrate 2; (4) add alkali to neutralize: add bottom water in the reactor, then add the filter cake 2 collected in step (3), heat up to 20-50 ° C, add inorganic alkali to adjust the pH of the solution = 7-8, the filter cake is completely dissolved; (5) concentrated crystallization obtains the target product 1-amino-4-naphthalenesulfonate sodium. The method of the invention has the characteristics of simple production process, low energy consumption, less waste water, high product selectivity and high purity.

Description

technical field [0001] The invention relates to a production method of a chemical dye intermediate, in particular to a production method of sodium 1-amino-4-naphthalenesulfonate. Background technique [0002] Sodium 1-amino-4-naphthalenesulfonate (sodium 1,4-acid for short) is widely used in chemical industry, medical treatment, dyestuff and other fields. At present, its main production process is the traditional solid-phase sulfonation method and solvent sulfonation method. Regardless of the solid-phase sulfonation method or the solvent sulfonation method, the source 1-nitronaphthalene is generally hydrogenated and reduced to obtain 1-naphthylamine, and 1-naphthylamine is then subjected to high-temperature transposition sulfonation to obtain sodium 1,4 acid. The synthetic route is relatively complicated. Among them, 1-naphthylamine belongs to Class 3 carcinogens and has certain carcinogenicity; and in the process of synthesizing 1-naphthylamine by high-pressure hydrogenati...

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Problems solved by technology

[0006] For the current traditional solid-phase sulfonation and solvent sulfonation methods to prepare sodium 1,4-acid, the process route is cumbersome, there are potential safety hazards in the preparation of intermediate products, a large amount of waste water is produced during the production process, and the intermediate products are strongly carcinogenic , high sulfonation reaction temperature, high energy consumption, easy carbonization of the product, easy loss of solvent and difficult recovery, etc., the present invention provides a kind of 1-nitronaphthalene and reducing sulfonating agent through the reduction sulfonation reaction of 1-nitronaphthalene and reducing sulfonating agent. The method of sodium 1-amino-4-naphthalenesulfonate, the method has simple production process, low energy consumption, less waste water, higher product selectivity and purity

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