Preparation method of N,N'-dialkyl m-phenylenediamine

The invention discloses a preparation method of N,N'-dialkyl m-phenylenediamine, which comprises the following steps: enabling NaBH4, I2, N,N'-dialkyl acyl m-phenylenediamine and THF (Tetrahydrofuran) as a solvent to react for 0.5 to 2 hours at the temperature of 5 to 10 DEG C; heating to 50 DEG C to the reflux temperature to react; and postprocessing the reaction solution to prepare the N,N'-dialkyl m-phenylenediamine after completely finishing a TCL monitoring reaction, wherein the amount ratio of the NaBH4 to the N,N'-dialkyl acyl m-phenylenediamine is 3-6:1; and the amount ratio of the I2 to the N,N'-dialkyl acyl m-phenylenediamine is 1-2:1. Compared with a LiAlH4 reduction system, the invention has the advantages that the reduction system does not require strict anhydrous reaction environment so that the solvent does not required to be dehydrated; the reductibility is milder than the reductibility of the LiAlH4; the safety and the controllability are greatly enhanced; the by-products are reduced so that