m-Phenylenediamine is an important organic synthesis raw material, mainly used as a dye intermediate, used in the manufacture of basic orange, basic brown G, direct lightfast black G and other dyes, and used as fur dyes, and epoxy resins are also used. It can also be used as a curing agent and a coagulant of cement, and used in mordant, color developer, etc. It can also be used as petroleum additives and raw materials for the manufacture of pharmaceuticals, and as a photometric reagent for the determination of nitrite and active chlorine in water. Among them, high-quality m-phenylenediamine, which is called polymer-grade m-phenylenediamine in the industry, is mainly used to synthesize high-end new material-meta-aramid fiber.