The present invention relates to a process for preparing N,N-substituted 1,3-propanediamine by a) reacting secondary amine with acrolein at a temperature of from (−50) to 100° C. and a pressure of from 0.01 to 300 bar, and b) reacting the reaction mixture obtained in stage a) with hydrogen and ammonia in the presence of a hydrogenation catalyst at a temperature of from 40 to 400° C. and a pressure of from 1 to 400 bar, wherein the molar ratio of secondary amine to acrolein in stage a) is 2:1 or more and the hydrogenation catalyst used in stage b) comprises cobalt. In a preferred embodiment, acrolein which has been obtained from glycerol based on renewable raw materials is used. The invention further relates to the use of N,N-dimethyl-1,3-propanediamine (DMAPA) based on renewable raw materials as a feedstock for lubricant soaps and other detergents, coagulants, polymers and comb polymers. In a further preferred embodiment, stage b) is performed in the presence of water.