Selective Synthesis of N , N ‐Bis(3‐dimethylaminopropyl)amine over Pd/γ‐Al 2 O 3

The synthesis of N , N ‐bis(3‐dimethylaminopropyl)amine (BPA) from 3‐(dimethylamino)‐propionitrile (PN) and 3‐( N , N ‐dimethylamino)propylamine (PA) over Pd/γ‐Al 2 O 3 in autoclaves was investigated. A series of Pd catalysts were prepared by different methods and characterized by XRD, TEM, and N 2 adsorption–desorption. It was found that their activities were obviously affected by calcination temperature and reducing agent. Among them, the catalyst calcined at 500 °C and reduced with NaBH 4 exhibited the best performance in this reaction. It was possibly attributed to the better dispersion of palladium particles on γ‐Al 2 O 3 . Furthermore, reaction parameters were also optimized. Under optimal conditions (PN/PA molar radio 1:1, toluene as solvent), BPA was obtained in 87.9% yield with 95.6% conversion over the above catalyst. Meanwhile, split of PN was observed. A probable mechanism of retro‐Michael reaction was also proposed.