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.