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Method for producing 4-aminotoluene-3-sulfonic acid

An aminotoluene, production method technology, applied in the preparation of sulfonic acid, organic chemistry and other directions, can solve the problem of high sulfonation reaction temperature, achieve the effects of sufficient sulfonation reaction, reduce environmental pollution, and improve quality and yield

Inactive Publication Date: 2008-03-19
ZHENJIANG DANTU TIANLONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method of the present invention does not need to use nicotinic acid as a sulfonating agent, and can overcome the defect of high sulfonation reaction temperature in the baking process, and solve the problem that the existing solvent method still needs to be processed to obtain high-purity (≥99%) 4B acid. The technical problem of purification, the inventive method can improve the quality and the yield of 4B acid, reduces environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 55 grams of p-toluidine was added to a stirred reactor equipped with 257 milliliters of chlorobenzene. After the p-toluidine was dissolved, 30 milliliters of 98% sulfuric acid was added dropwise within 2 hours under stirring. During the process, the temperature of the reactant was raised to 120°C, and after maintaining stirring for 60 minutes, the temperature of the reactant was raised to 190°C to carry out the sulfonation reaction. Condensate and discharge. After the reaction is completed, carry out vacuum distillation for about 2 hours, the pressure is -930KPa, the temperature is 190-202°C, until it is evaporated to dryness, and the evaporated solvent is condensed and recovered. The material after vacuum distillation was cooled to room temperature to obtain 94.5 g of product 4B acid with a yield of 98.3%.

[0021] The resulting 4B acid product has a purity of 98.6%.

Embodiment 2

[0023] 120 grams of p-toluidine was added to a stirred reactor equipped with 500 milliliters of chlorobenzene. After the p-toluidine was dissolved, under stirring, 65.4 milliliters of 98% sulfuric acid was added dropwise within 1.5 hours. During the process, the temperature of the reactants was raised to 110 ℃ , after maintaining stirring for 90 minutes, the temperature of the reactant was raised to 185°C for sulfonation reaction, kept at 185-190°C under normal pressure for 4 hours, the water generated during the reaction was continuously distilled out, and then discharged after condensation. After the reaction is completed, carry out vacuum distillation, the pressure is -960KPa, the temperature is 195 ~ 205 ° C, until it is evaporated to dryness, and the evaporated solvent is condensed and recovered. The material after vacuum distillation was cooled to room temperature to obtain 206 g of product 4B-acid with a yield of 98.2%.

[0024] The resulting 4B acid product has a puri...

Embodiment 3

[0026] Add 60 grams of p-toluidine to a stirred reactor equipped with 260 milliliters of chlorobenzene (200 milliliters of which is the solvent recovered), and after the p-toluidine is dissolved, add it dropwise within 2 hours under stirring. 32 milliliters of 98% sulfuric acid, the temperature of the reactant is raised to 120°C during the dropping process, and after maintaining stirring for 90 minutes, the temperature of the reactant is raised to 185°C for sulfonation reaction, and the temperature is kept at 185-190°C for 5 hours under normal pressure. The water produced in the process is continuously evaporated and discharged after condensation. After the reaction is completed, carry out vacuum distillation, the pressure is -960KPa, the temperature is 195 ~ 205 ° C, until it is evaporated to dryness, and the evaporated solvent is condensed and recovered. The material after vacuum distillation was cooled to room temperature to obtain 103.8 g of product 4B-acid with a yield of...

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Abstract

The invention discloses a production method of 4-aminotoluene-3-sulfonic acid. Toluidine is resolved in organic solution and added with concentrated sulphuric acid which being stried, after the addition of the concentrated sulphuric acid is finished, the stiring lasts for one to two hours, the temperature of reactant is raised to 180 DEG C to 190 DEG C for a sulphonation reaction, which lasts for three to six hours, and the water generated in the course of the reaction is constantly evaporated and then discharged after being condensed; after the reaction is finished, solvent is recovered by decompression distillation and cooled down in order to produce the 4-aminotoluene-3-sulfonic acid. According to the method of the invention, the concentrated sulphuric acid is used as sulfonating agent, the toluidine undergoes the sulphonation reaction under a low temperature, and the purity of the produced 4-aminotoluene-3-sulfonic acid product is high, reaching over ninety nine percent; the sulphonation reaction is sufficient, and the yield rate of products is high; the solution can be reused, so pollution discharge is reduced. The method of the invention has the advantages of increase of the quality and yield rate of products, reduction of environmental pollution and great reduction of production cost.

Description

technical field [0001] The present invention relates to a kind of production method of organic intermediate, especially relate to a kind of production method of 4-aminotoluene-3-sulfonic acid (4B acid). Background technique [0002] 4B acid (4-Aminotoluene-3-Sulfonic Acid), chemical name 4-aminotoluene-3-sulfonic acid, white or beige powder crystal, is an important intermediate for the synthesis of various pigments and reactive dyes. In particular, it is coupled with 2,3-acid after diazotization, and then laked with calcium chloride, which can produce Pigment Red 57:1, one of the three main red pigments. At present, the output of pigment red 57:1 in my country is relatively low, which cannot meet the needs of domestic and foreign markets. The main reason is that there are few manufacturers of 4B acid as one of the main raw materials, the technology is backward, and the product quality is poor. [0003] One of the production methods of 4B acid is derived from the sulfonation...

Claims

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Application Information

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IPC IPC(8): C07C309/46C07C303/06
Inventor 董为民陈淑华俞杨朱肇树张广路
Owner ZHENJIANG DANTU TIANLONG CHEM
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