Promotional Effect of Cu for Catalytic Amination of Diethylene Glycol with Tertiarybutylamine over Ni–Cu/Al2O3 Catalysts

Abstract

In this work, we synthesized a series of 20% Ni-x% Cu/Al2O3 catalysts containing various Cu loading by the impregnation method and investigated their catalytic performance in the amination of diethylene glycol (DEG) with tertiarybutylamine (TBA) to tertiarybutylaminoethoxyethanol (TBEE). A variety of characterization techniques including XRD, TEM, BET, XPS, H2-TPR, NH3-TPD, CO2-TPD were applied. The promotional influence of Cu on the catalytic performance of Ni/Al2O3 catalyst was studied, and the optimal addition of Cu was obtained. Indeed, we found that Ni–Cu alloy was formed after reduction of the Ni–Cu/Al2O3 catalysts. Due to the strong interaction between Cu and Ni, Cu could improve the reducibility of NiO and the dispersion of Ni species on the catalyst surface, which were critical factors for higher reactivity of the bimetallic Ni–Cu/Al2O3 catalysts. Moreover, the influence of catalyst reduction temperature and reaction temperature were examined. When operating at 230 °C, the 20% Ni-10% Cu/Al2O3 catalyst reduced at 500 °C for 2 h exhibited superior catalytic performance in this reaction. Ni-Cu/Al2O3 catalyst was found to be an effective catalyst for catalytic amination of diethylene glycol with tertiarybutylamine.