The synthesis of asymmetric ethylenediamine derivatives catalyzed by ion-exchange resins

The ring-opening reaction of aziridine with alkylamines over a series of ion-exchange resins was investigated. Among these catalysts, D001-CC exhibited excellent catalytic performance. The catalysts were characterized by SEM and N2 adsorption–desorption. The results indicated that the selectivity of N,N-diethylethylenediamine mainly depended on the acidity and SBET of the resins. Strong Brönsted acid sites played an important role on the conversion of aziridine, and the distribution of acid sites on catalyst had a significant effect on the selectivity of N,N-diethylethylenediamine. The reaction parameters, such as reaction time, molar ratio, reaction temperature, and catalyst loading, were also optimized and N,N-diethylethylenediamine was obtained in an excellent yield of 97 %. Furthermore, D001-CC was efficiently recycled five times by simple treatment with large amounts of deionized water and mineral acid. Finally, a series of asymmetric ethylenediamine derivatives were successfully synthesized with this method. Therefore, a simple and versatile process for the synthesis of asymmetric ethylenediamine derivatives has been established over ion-exchange resins.