CO2-Product-Driven Integrated Carbon Capture and Utilization to Produce Cyclic Carbonates

There is an urgent need to develop energy-efficient solutions for CO2 capture and utilization, because current integrated processes remain limited by the compatibility of the capture and conversion stages. This work proposes a novel product-driven carbon capture and utilization concept, in which the CO2-derived cyclic carbonate product is sequentially employed as a physical CO2 absorbent and subsequently as the reaction medium for its own synthesis, eliminating the intermediate solvent regeneration step. Density, viscosity, and CO2 solubility were experimentally determined for four cyclic carbonates, while cycloaddition reactions were performed under representative integrated process conditions using the ionic liquid [bmim]I as a catalyst. The complete process for natural gas purification was evaluated through conductor-like screening model (COSMO)-based/Aspen process simulation and life cycle assessment. Experimental and computational results demonstrate that propylene, butylene, and hexylene carbonates provide competitive CO2 absorption performance, extending the applicability of the proposed concept to other CO2-derived cyclic carbonates. More importantly, the direct use of the CO2-rich cyclic carbonate stream as the reaction medium was experimentally validated without significant thermodynamic or kinetic limitations despite the high product concentration. The proposed concept achieves a competitive energy demand and CO2-related emissions while avoiding deep vacuum operation and intermediate solvent regeneration.