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Process for synthesizing 2,4-diamino benzene sulfonic acid and its salt

A diaminobenzenesulfonic acid and sulfuric acid technology, applied in 2 fields, can solve problems such as rising production costs and environmental pollution

Inactive Publication Date: 2007-01-24
SHANGHAI WORLD PROSPECT INT TRADE +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The object of the present invention is to provide a kind of preparation 2, the method for 4-diaminobenzenesulfonic acid, this method can overcome the problem of environmental pollution and production cost rise owing to needing to use a large amount of sulfuric acid in the prior art
[0008] The inventor of the present invention finds after in-depth research, prepares 2,4-diaminobenzenesulfonic acid by sulfonating m-phenylenediamine with sulfuric acid or oleum in a specific solvent, which can effectively solve the problems caused by the use in the prior art. Environmental pollution caused by a large amount of sulfuric acid and the problems of rising production costs can obtain higher reaction yield and product quality at the same time

Method used

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  • Process for synthesizing 2,4-diamino benzene sulfonic acid and its salt
  • Process for synthesizing 2,4-diamino benzene sulfonic acid and its salt

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[0027] In the preparation method of the present invention, the inorganic solvent and the organic solvent may be used alone or in combination. When the inorganic solvent and the organic solvent are used in combination, the specific dosage can be determined according to the above description of the dosage of the inorganic solvent and the organic solvent.

[0028] In the preparation method of the present invention, the sulfonation reaction is carried out in the temperature range of 140-250°C, preferably in the temperature range of 160-210°C, particularly preferably in the temperature range of 170-200°C.

[0029] "Sulfuric acid" as used in the present invention refers to sulfuric acid of any concentration or oleum of any concentration diluted with water to sulfuric acid of any concentration. For example, the sulfuric acid used in the present invention may be 0.1-100% sulfuric acid or any concentration of oleum diluted with water to 0.1-100% sulfuric acid. The sulfuric acid is mor...

Embodiment 1

[0038] To a reactor equipped with a condenser with an oil-water liquid separator was added 300 g of o-dichlorobenzene, 100 ml of 98% sulfuric acid (184 g) (equivalent to 180 g of 100% sulfuric acid or 1.84 moles of 100% sulfuric acid) and 100% 100 grams of m-phenylenediamine (equivalent to 0.926 moles), warmed up to 175 ° C, reacted at 175 to 180 ° C for 4 hours, cooled, added 400 ml of water, separated the organic phase and the water phase, the organic phase can be used for the next batch reaction The solvent, the aqueous phase was purified and decolorized to obtain 168.8 g of 2,4-diaminobenzenesulfonic acid. The appearance of the obtained product is white crystal, the chromatographic content is 99% (determined by HPLC), the chemical content is 98% (determined by diazo titration), and the product yield is 95% (calculated by m-phenylenediamine).

Embodiment 2

[0040] To the reactor, add 30 grams of phosphoric acid, 155 grams of 98% sulfuric acid (equivalent to 150 grams of 100% sulfuric acid) and 100 grams of 100% m-phenylenediamine, heat up to 195 ° C, react at 195 to 200 ° C for 6 hours, cool, 400 ml of water was added, and the aqueous phase was purified and decolorized to obtain 168.0 g of 2,4-diaminobenzenesulfonic acid. The appearance of the obtained product is white crystal, the chromatographic content is 99% (determined by HPLC), the chemical content is 98% (determined by diazo titration), and the product yield is 95% (calculated by m-phenylenediamine).

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Abstract

The process of synthesizing 2, 4-diamino benzene sulfonic acid includes the following steps: the reaction between m-phenylene diamine and sulfuric acid inside solvent at 140-250 deg.c, with the solvent being one or several selected from inorganic solvent phosphoric acid and polyphosphoric acid and organic solvent with normal pressure boiling point over 140deg.c. The present invention also discloses the preparation process of 2, 4-diamino benzene sulfonate, which is prepared through the first preparing 2, 4-diamino benzene sulfonic acid and the subsequent salt forming reaction to obtain 2, 4-diamino benzene sulfonate. The present invention has less sulfuric acid consumption, less environmental pollution, low cost, high yield and high product quality.

Description

technical field [0001] The present invention relates to a synthetic method of 2,4-diaminobenzenesulfonic acid and its salts. Background technique [0002] 2,4-Diaminobenzenesulfonic acid, also known as m-phenylenediamine-4-sulfonic acid, has the following structural formula: [0003] [0004] 2,4-Diaminobenzenesulfonic acid and its salts (especially sodium salts) are mainly used as important intermediates in the synthesis of dyes, and their derivatives have been widely used in our production and life. [0005] A conventional method for preparing 2,4-diaminobenzenesulfonic acid is as follows: using 2,4-dinitrochlorobenzene as a raw material, reacting with sodium bisulfite and then reducing it to obtain it. The disadvantages of this method are low reaction yield, poor product quality and low production efficiency. [0006] The prior art discloses another method for preparing 2,4-diaminobenzenesulfonic acid (for example, Japanese Patent Publication Sho 57-48961, Japanese P...

Claims

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Application Information

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IPC IPC(8): C07C309/46C07C303/04
CPCC07C303/32C07C303/06
Inventor 唐会林许晓峻
Owner SHANGHAI WORLD PROSPECT INT TRADE
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