Kinetics of Diethyl Oxalate Hydrogenation Over Cu/SiO ₂ Catalyst: Influence of Nickel as a Promoter

ABSTRACT The hydrogenation of diethyl oxalate (DEO) to monoethylene glycol (MEG) is an essential step toward developing an alternative MEG synthesis process that enables flexible utilization of carbon resources. Copper‐based catalysts have been extensively studied for dimethyl oxalate (DMO) hydrogenation. However, their long‐term stability remains a critical limitation, restricting their potential for industrial‐scale application. The current study investigates nickel‐promoted Cu/SiO 2 catalysts with optimized nickel content. The catalyst was prepared using the urea gel method and characterized by BET SA, XRD, TEM, and XPS to analyze its surface and chemical properties. At the optimal reaction conditions of 513 K, 2.5 MPa pressure, LHSV of 1 h −1 , and H 2 /DEO ratio of 25 mol/mol, the time‐on‐stream study demonstrated 50 h of stable catalytic performance. Furthermore, the reaction kinetics were modeled using the power law and the Langmuir‐Hinshelwood mechanism. Based on different conditions, 18 kinetic models were developed, and model discrimination and parameters were estimated. The results indicate that the reaction proceeds via the dissociative adsorption of DEO and H 2 on two different sites, with the surface reaction being the rate‐controlling step.