Method for continuously and efficiently synthesizing m-phenylenediamine based on fixed bed microreactor

The invention discloses a method for continuously and efficiently synthesizing m-phenylenediamine based on a fixed bed microreactor, which comprises the following steps: (1) taking m-dinitrobenzene as a raw material, and dissolving the m-dinitrobenzene in a solvent to serve as a substrate solution to be hydrogenated; (2) mixing a to-be-hydrogenated substrate solution and hydrogen in a micro-mixer to form a gas-liquid mixture with a good gas-liquid micro-dispersion state, and then enabling the gas-liquid mixture to enter a micro-packed bed reactor filled with a solid particle catalyst to react, wherein the reaction temperature is 40-160 DEG C, the pressure is 1-5 MPa, and the retention time of the gas-liquid mixture in the micro-packed bed reactor is 10-120 s; and (3) carrying out gas-liquid separation on a gas-liquid mixture obtained after the reaction is finished, and feeding a liquid product into a subsequent separation and purification system. The method is convenient to operate, controllable in heat relea