Tailoring Basicity and Surface Structure in CaO/Activated Carbon Catalysts for High-Performance Diethyl Carbonate Synthesis

The synthesis of diethyl carbonate (DEC) faces several challenges, including the difficulty in separating and recycling highly active organic alkali catalysts, poor catalyst stability, and high operational costs associated with traditional transesterification methods. Additionally, industrial transesterification processes often suffer from low production capacity and slow reaction kinetics. In this study, we explore the catalytic performance of various metal-compound-based catalysts supported on commercial activated carbon (AC) in a fixed-bed reactor. The development of highly stable and long-life catalysts reduces production costs, while ensuring efficiency, selectivity and stability, and provides a technical reference for the industry to realize continuous production. Among the tested catalysts, 4CaO/AC-600 exhibited the highest catalytic activity, achieving a DMC conversion of 94% and DEC selectivity exceeding 60% under optimal conditions. Characterization results suggest that the excellent performance of 4CaO/AC-600 stems from the following synergistic mechanisms: the strongly basic sites can drive the transesterification reaction efficiently; the porous structure promotes the active site dispersion and reactant diffusion; and the interaction between CaO and AC enhances the structural stability and electronic effect. Furthermore, this study offers valuable insights into the design of efficient catalysts for the industrial-scale synthesis of DEC.