Preparation method of dye intermediate 3-(beta-hydroxyethyl sulfonyl) aniline

Abstract

The invention discloses a preparation method of dye intermediate 3-(beta-hydroxyethyl sulfonyl) aniline. The preparation method comprises the following steps: carrying out chlorosulfonation reaction on nitrobenzene and chlorosulfonic acid to obtain m-nitrobenzenesulfonyl chloride; reducing m-nitrobenzenesulfonyl chloride by using sodium pyrosulfite, and regulating the pH value of a reaction solution to 7.4-7.7 in the reaction process; adding sodium chloride after the reaction is finished, and salting out to obtain a reduction product; wherein the molar ratio of sodium pyrosulfite to m-nitrobenzenesulfonyl chloride to sodium chloride is (0.68-0.685): 1: (0.54-0.58); adding ethylene oxide into the reduction product, controlling the PH value to be 7-7.5, and reacting to obtain a condensationproduct; adopting stannous chloride and a Pd / C catalyst for reducing the condensation product to obtain 3-(beta-hydroxyethyl sulfonyl) aniline, wherein the molar ratio of the condensation product to the Pd / C catalyst is (0.45-0.46): 1: 0.0012. The preparation method provided by the invention can effectively inhibit the generation of byproducts in each process link, not only can improve the productquality, but also reduce environmental pollutants, and has a green and environment-friendly effect.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and more specifically relates to a preparation method of a dye intermediate 3-(β-hydroxyethylsulfone) aniline. Background technique [0002] In recent years, China's dye industry has continued to develop rapidly. China's dye output has ranked first in the world, accounting for about 60% of the world's total share. It is the most important production country and supply area for intermediates. [0003] 3-(β-hydroxyethylsulfone)-nitrobenzene is an important dye intermediate with a wide range of market applications; [0004] At present, 3-(β-hydroxyethylsulfone)-nitrobenzene is produced by using nitrobenzene as a raw material, which is formed by chlorosulfonation, sulfuryl chloride reduction, condensation, and iron powder reduction; among them, in the chlorosulfonation link , in order to increase the yield, a large amount of chlorosulfonic acid must be used to participate in the reaction, ...

AI Technical Summary

Problems solved by technology

[0004] At present, 3-(β-hydroxyethylsulfone)-nitrobenzene is produced by using nitrobenzene as a raw material, which is formed by chlorosulfonation, sulfuryl chloride reduction, condensation, and iron powder reduction; among them, in the chlorosulfonation link , in order to increase the yield, a large amount of chlorosulfonic acid must be used to participate in the reaction, and a large amount of sulfuric acid waste water is produced, which is difficult to recycle and causes corrosion to the equipment; in the condensation link, ethylene oxide or chlorohydrin is used as the condensation agent, ethylene oxide or Chlorohydrin is easily hydrolyzed at high temperature, resulting in low purity and low yield of condensation products; and excessive use of condensing agent will lead to increased cost; in the reduction link, although iron powder can be used as a reducing agent to obtain a higher yield, the reaction After that, there will be a large amount of iron sludge that is difficult to handle, which will seriously pollute the environment;

[0005] In summary, the current 3-(β-hydroxyethylsulfone) aniline synthesis process has the disadvantages of low product yield, environmental pollution, and insufficient environmental protection