2,5-dimethyl-1,4-phenylenediamine preparation method

The invention relates to a preparation method of 2,5-dimethyl-1,4-phenylenediamine. The method is characterized in that aniline substances are used as a raw material and are made into 2,5-dimethyl-1,4-phenylenediamine through a diazotization reaction, a coupled reaction, a hydrogenolysis reaction and purification treatment. According to the invention, the main and the auxiliary raw materials are cheap and easy to obtain, the reaction steps are relatively few, the yield is high, the operation is simple and convenient, and the method is used for further replacing the old technology to realize and develop the novel industrialized production of the product; the aniline substances are reclaimed to be still used as auxiliary raw materials for preparing aniline diazonium salt, so that cost and pollution are reduced, circular economy is produced, and cleaner production is realized; the quality of the obtained product is improved greatly, and the content is far more than the old product, especially an exported product of the content of 75%; the prepared product can not only be used for dye and paints, but also can expand using functions of a high-performance material monomer.