Catalytic Synthesis of Morpholine from Diethylene Glycol Over Ni, Zno Thermally Stable Cu-Based Catalysts Prepared by Hydrothermal-Co-Precipitation

Abstract

Cu-based catalysts exhibit high activity in converting alcohols to amines but are prone to sintering at high temperatures. Alloying has long been recognized as an effective method of improving catalytic performance. Therefore, this paper proposes a novel improvement strategy. Firstly, Al2O3-supported multimetallic catalysts prepared by the co-precipitation method were subjected to hydrothermal treatment, successfully constructing ternary alloy catalysts. Secondly, the formation of the catalyst surface structure was controlled by adjusting the metal ratios. It has been shown that Zn plays a connecting role in the formation of alloys. The combined effect of Zn and Ni enhanced the catalytic activity of CuNiZn/Al2O3 catalysts. The Cu2.0Ni2.0Zn1.0/Al2O3 catalyst achieved a morpholine yield of 93% and exhibited excellent thermal stability, with a less than 2% decrease in initial diethylene glycol conversion after 50 hours of continuous reaction. This newly developed thermally stabilized CuNiZn/Al2O3 catalyst shows great potential for commercial applications.

Keywords: Cu-Based Catalyst, DEG Synthesis of MPH, CuNiZn Alloying, Thermal Stability