Synthetic method of paratonere 57:1

Abstract

The invention discloses a synthetic method of paratonere 57:1, which comprises the steps of coupling diazo salt of 4-aminotoluene-3-sulfonic acid with solution of 3-hydroxy-2 naphthalenecarboxylic acid sodium salt, and using an inorganic calcium compound as a color lake for preparing the paratonere 57:1. The synthetic method adopts the solution of the 3-hydroxy-2 naphthalenecarboxylic acid sodium salt for carrying out coupling reaction and can solve adverse factors of packaging, transportation, storage and artificial feeding caused by adopting solid 3-hydroxy-2 naphthalenecarboxylic acid in the prior art and reduce the environmental impacts and hazard caused by exposure; as the solution of the 3-hydroxy-2 naphthalenecarboxylic acid sodium salt is liquid, and the liquid has solubility and uniformity, the synthetic method can better accurately determine the actual content of the 3-hydroxy-2 naphthalenecarboxylic acid; and the synthetic method can lead the whole production process to realize no emission of waste solution, save processing cost and save production cost.

Description

technical field [0001] The invention relates to a method for synthesizing pigments, in particular to a method for synthesizing Pigment Red 57:1. Background technique [0002] The current state of the art for the synthesis of Pigment Red 57:1 (i.e. C.I. Pigment Red 57:1) is to obtain an azo dye by coupling the diazonium salt of 4-aminotoluene-3 sulfonic acid with 3-hydroxyl-2 naphthoic acid, Then the azo dye is further prepared by laking it with an inorganic calcium compound. [0003] The reaction rate in the case of obtaining the diazonium salt of 4-aminotoluene-3-sulfonic acid is more than 98%, which is basically stipulated by stoichiometry. For this reason, the 4-aminotoluene- The feed molar ratio of the diazonium salt of 3-sulfonic acid and 3-hydroxyl-2-naphthoic acid is sometimes represented by 4-aminotoluene-3-sulfonic acid: 3-hydroxyl-2-naphthoic acid (molar ratio), but , in this coupling reaction, the theoretical molar ratio of the two is 1:1, considering the reacti...

AI Technical Summary

Problems solved by technology

As we all know, the existence of factors such as damage, exposure, and volatilization during the transportation, storage and use of solid materials can easily cause environmental pollution.

Especially in the process of feeding and using, it is easy to diffuse and float small solid particles in the air due to the dust relationship of 3-hydroxy-2 naphthoic acid, which brings health hazards to customers in the process of handling them.