Preparation method for 2,5-dichloro-1,4-phenylenediamine

The invention relates to a preparation method for 2,5-dichloro-1,4-phenylenediamine. A new route is realized in such a way that 2,5-dichloroaniline is used as a raw material and coupled with aniline diazonium salt to prepare an azo-compound in advance, and then zinc is added for reduction and hydrogenolysis under an acidic condition to prepare 2,5-dichloro-1,4-phenylenediamine, the 2,5-dichloro-1,4-phenylenediamine produced through reduction is subjected to decoloring neutralization after being taken out in the form of hydrochlorate, and meanwhile, the recovery circulation technology is adopted for steam distillation to recover aniline which is recycled for preparing aniline diazonium salt. The preparation method has the characteristics that the yield is improved, the cost is lowered, the pollution is reduced, and cleaner production is realized while circular economy is produced.