Preparation method of intermediate 2, 5-diarylamino-terephthalic acid

The invention discloses a preparation method of an intermediate 2, 5-diarylamino-terephthalic acid, and belongs to the field of organic chemical synthesis. The preparation method comprises the following steps: S1, under a low-temperature condition, fully mixing dimethyl succinylsuccinate, arylamine and inorganic acid in an ethanol solution, and carrying out condensation reaction on the dimethyl succinylsuccinate and the arylamine in a reflux state; s2, adding a catalyst and alkali metal hydroxide into the reaction liquid obtained in the step S1, and adding hydrogen peroxide in a distillation or reflux state for oxidation; and S3, diluting the reaction solution obtained in S2 with water, filtering to obtain a catalyst and filtrate, adding water into the filtrate for dilution, adding acid into the filtrate for acidification, filtering, washing, and drying to obtain the quinacridone intermediate. According to the method, the quinacridone intermediate with high purity and high yield can be prepared, the ethanol,