Continuous synthesis of N-ethylethylenediamine over supported Cu-Zn-La catalysts

A series of Cu-based catalysts were prepared and employed in the N-ethylation of ethylenediamine with ethanol in a fixed-bed reactor. Satisfying results were obtained using Cu-Zn-La/Al2O3 as a catalyst. In addition, Cu-Zn-La/SiO2, Cu-Zn-La/Al2O3 and Cu-Zn-La/HZSM-5 were characterized by the Brunauer-Emmett-Teller method (BET), H2- temperature program reduction (H2-TPR), X-ray diffraction (XRD), transmission electron microscopic measurements (TEM) and NH3-temperature programmed desorption (NH3-TPD) in order to investigate the influence of supports on their catalytic performance. It was found that both the BET surface area and the acidity of the support are key factors in the catalytic performance. Moreover, reaction parameters including temperature, hydrogen pressure and liquid hourly space velocity were optimized. Under optimal conditions, a 73.3 % conversion of ethylenediamine and a 71.2 % selectivity of N-ethylethylenediamine were achieved. Finally, the lifetime of the catalysts was evaluated and the reaction proceeded con-tinuously for over 200 h.