Method for recovering 4-nitroisophthalic acid by using 5-nitroisophthalic acid production mother liquor

• Main Authors: YAO GUOBIN, CHEN HAIHUA, ZHOU JIANJUN, ZHANG XIANGHUA, ZHENG JINPENG
• Format: Patent
• Language: Chinese; English
• Published: 12.07.2024
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

The invention relates to the technical field of chemical medicines, in particular to a method for recycling 4-nitroisophthalic acid from 5-nitroisophthalic acid production mother liquor. The method comprises the following steps: S1, neutralizing the 5-nitroisophthalic acid production mother liquor by using an alkaline substance A until the pH value is 0.5-3; s2, carrying out adsorption treatment on the mother liquor of which the pH is adjusted in the step S1 by adopting weakly alkaline anion exchange resin; s3, eluting the resin obtained in S2 by using an alkaline substance B; s4, acidifying the eluent obtained in S3 until the pH value is 1-6, preserving heat, crystallizing, and filtering to obtain a 4-nitroisophthalic acid crude product; s5, carrying out recrystallization on the 4-nitroisophthalic acid crude product, and filtering; and S6, pulping the filter cake obtained in the step S5 by using an acid solution, filtering, and drying to obtain a 4-nitroisophthalic acid finished product. According to the pro