Homogeneous and heterogeneous ionic liquids catalyze CO2 cycloaddition reaction

Abstract

The synthesis of cyclic carbonates, which are essential solvents for lithium-ion batteries, through the cycloaddition of carbon dioxide (CO₂) and epoxides, and further ester exchange with methanol to form linear carbonates has always been one of the effective ways for CO₂ resource utilization. In this work, the kinetics and reactor technology selection of ionic liquids as catalysts for CO₂ conversion were analyzed from the perspective of process systems engineering. Firstly, ethanol (EtOH) was used as the solvent, and 1‑butyl‑3-methylimidazolium bromide ([Bmim] Br) was used to catalyze the CO₂ cycloaddition reaction in a batch reactor. The effect of reaction conditions on the kinetic performance of synthesizing propylene carbonate (PC) was studied. Secondly, a supported polyelectrolyte liquid membrane was designed and prepared, and a continuous ionic liquid membrane reactor was established for the continuous catalytic reaction of CO₂ and epichlorohydrin (PO). The performance of the continuous catalytic reaction was studied and compared with batch reaction experiments. Based on the results of kinetic experiments, the reaction order of the reaction rate equation and the activation energy in the reaction system were determined. Finally, under the premise of achieving high PC yield goals and optimizing process conditions, a dual zone dynamic modeling was conducted on the batch reactor to guide the comprehensive evaluation of technology, economy, and environment under uncertain conditions, laying the foundation for the pilot scale clean production of high-value chemicals synthesized by chemical conversion of CO₂.