Highly efficient synthesis of cyclic carbonates via deep eutectic solvents from CO2 at the gas-liquid interface of microdroplet under atmospheric pressure condition

The cycloaddition reaction of CO2 in traditional reactors is relatively slow due to insufficient gas-liquid contact. In this work, the microdroplet reactor was set up to research the intensification effect of increasing the volumetric mass transfer coefficient on the reaction. The [C1C2Im][I]/PhOH (1-ethyl-3-methylimidazolium iodide/ Phenol) with a molar ratio of 2:1 exhibited excellent catalytic activity at room temperature. Up to 85% conversion of the substrate could be achieved in the microdroplet intensification device. The intensification reaction model of the microdroplet was established, which explored the effect of the microdroplet size and gas-liquid mass transfer on the reaction. The increase of the volumetric mass transfer coefficient (kLa) could improve the efficiency of the reaction at the gas-liquid interface of the microdroplet. The mathematical model of the microdroplet intensification reaction was established to clarify the intensification mechanism.