A Biomass‐Ligand‐Based Ru(III) Complex as a Catalyst for Cycloaddition of CO2 and Epoxides to Cyclic Carbonates and a Study of the Mechanism

Abstract Aiming highly efficient conversion of greenhouse gas CO 2 to cyclic carbonates, a biomass Ru(III) Schiff base complex catalyst ( SalRu ) was constructed by employing a derivative of Lignin degradation (5‐aldehyde vanillin). The SalRu catalyst had a remarkable conversion for epoxides into corresponding cyclic carbonates even at atmospheric pressure of CO 2 without the presence of co‐catalyst. As the condition at 120 °C and 2 MPa CO 2 the conversion reached to 94 % with selectivity at 99 % after 8 h. 32 % cyclic carbonate production was obtained even under 0.2 MPa CO 2 pressure. The epoxide activation and ring opening, CO 2 insertion and cyclic carbonate formation were illuminated explicitly through the of characteristic absorption peaks changing, which further providing direct and visual evidence for the mechanism proposing. This study has important theoretical significance for the comprehensive utilization of environmental pollutants and energy.