METHOD OF SEPARATION AND CLEANING OF PARA-AMINOBENZOIC ACID

摘要

FIELD: separation and cleaning of para-aminobenzoic acid. ^ SUBSTANCE: proposed method consists in increasing the concentration of salts of para-nitrobenzoic acid in reaction mass by obtaining the following ratio of sodium and ammonium salts: Na-salt : NH4-salt = 7.5-8.0 : 2.5-2.0 mole; acidation of solution of para-aminobenzoic acid is carried out with the aid of nitric acid at concentration of 20-25%. Novelty of invention consists in setting the required ratio of sodium and ammonium salts of para-nitrobenzoic acid and use of nitric acid for separation of para-aminobenzoic acid from solution. ^ EFFECT: increased productivity of equipment; high concentration of salts of para-nitrobenzoic acid; high purity of target product. ^ 2 cl, 1 tbl, 4 ex