The invention relates to a diamine industrially producing method from a corresponding alkenile-nitrile which contains at least one C-C double bond consisting (a) in reacting the alkenile-nitrile in a first reactor with a corresponding monoamine by exothermally adding a monoamine to said double bond in such a way that an aminoalkyle nitrile is obtained, wherein the monoamine and water are providedand the alkenile-nitrile is added, (b) in evaporating the unreacted alkenile-nitrile and aminoalkyle for enriching the aminoalkyle nitrile produces in the sump of the first reactor, (c) in transferring the aminoalkyle nitrile bottom product of the step (b) to a second reactor, (d) in batchwisely catalytically hydrogenating the aminoalkyle nitrile transferred at the step (c) in such a way that a diamine is produced in the second reactor, wherein for each batch,; an appropriate catalyst and water for hydrogenating nitrils into amines, a desired diamine and a base are provided, the second reactor is supplied with hydrogen and the aminoalkyle nitrile transferred at the step (c) is proportioned therein, and (e) in extracting the diamine and in possibly repeating the steps from (a) to (e). A device for producing the diamine and the use of the devices are also disclosed. The preferred diamine is embodied in the form of a 3-dimethylaminopropylamine (DMAPA).