p-phenylenediamine preparation method

The invention relates to a p-phenylenediamine preparation method, and belongs to the technical field of organic synthesis. According to the p-phenylenediamine preparation method, p-nitroaniline and amagnetic nanometer nickel hydrogenation catalyst are added to a reaction kettle, wherein the bottom portion of the reaction kettle is provide with an electromagnetic relay; after sealing, the reactionkettle is inflated with carbon dioxide to completely discharge air; heating is performed; inflating is performed with the mixed gas of carbon dioxide and hydrogen, and pressurizing is performed; after the reaction temperature and the required hydrogen pressure are achieved, a catalytic hydrogenation reaction on p-nitroaniline is performed to obtain p-phenylenediamine; and after the reaction is completed, the electromagnetic relay is started, cooling and pressure relieving are performed after 10 min, the discharged carbon dioxide is absorbed by an alkali solution, and the catalyst is magnetically adsorbed at the bottom