Preparation method of sulfonated para-ester serving as dye intermediate

Abstract

The invention relates to a preparation method of sulfonated para-ester serving as a dye intermediate. The method comprises the following steps of: (d) undergoing a sulfonation, esterification and hydrolysis reaction: adding para-beta-hydroxyethyl sulfuryl antifebrin into 105 percent sulfuric acid, controlling the temperature at 20-40 DEG C, stirring uniformly, slowly raising the temperature to 120 DEG C, reacting for 3.5 hours, lowering the temperature to 50 DEG C, dropwise adding water, raising the temperature to 96+ / -1 DEG C, undergoing a hydrolysis reaction for 10 hours, and lowering the temperature to 25 DEG C to obtain a sulfonated para-ester reaction liquid; (e) diluting; and (f) salting out to obtain the sulfonated para-ester. Compared with the conventional preparation process, the preparation method has the advantages of replacement of sulfonation, esterification and hydrolysis reactions in three independent units by a reaction in one unit and removal of waste acid produced by reactions in two units.

Description

technical field [0001] The invention relates to a preparation method of a dye intermediate, in particular to a preparation method of a dye intermediate sulfonated para-ester. Background technique [0002] Now the general method for preparing sulfonated para-ester is to generate p-β-hydroxyethyl sulfone acetanilide through chlorosulfonation, reduction reaction, and condensation reaction with ethylene oxide, and then through esterification and hydrolysis. Obtain p-β-hydroxyethyl sulfone sulfate aniline (para-ester), and finally make sulfonated para-ester through sulfonation reaction. The three unit reactions of this preparation method are esterification, sulfonation and hydrolysis. , the amount of waste acid produced is very large, which does not meet the current requirements for energy saving and emission reduction, and has caused serious pollution to the environment. Due to environmental ecology and waste liquid treatment cost constraints, the requirement for the amount of ...

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Problems solved by technology

[0002] Now the general method for preparing sulfonated para-ester is to generate p-β-hydroxyethyl sulfone acetanilide through chlorosulfonation, reduction reaction, and condensation reaction with ethylene oxide, and then through esterification and hydrolysis. Obtain p-β-hydroxyethyl sulfone sulfate aniline (para-ester), and finally make sulfonated para-ester through sulfonation reaction. The three unit reactions of this preparation method are esterification, sulfonation and hydrolysis. , the amount of waste acid produced is very large, which does not meet the current requirements for energy saving and emission reduction, and has caused serious pollution to the environment

Due to the constraints of environmental ecology and waste liquid treatment costs, the requirements for the amount of waste acid are getting higher and higher, and this preparation method can no longer meet the requirements of environmental protection.

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