Assessment of Green Chemistry Metrics for Carbon Dioxide Fixation into Cyclic Carbonates Using Eutectic Mixtures as Catalyst: Comprehensive Evaluation on the Example of a Tannic Acid-Derived System

The synthesis of cyclic carbonates, which utilizes CO2 as a feedstock, is among the transformations presenting an opportunity to reduce CO2 emissions, while enhancing independence from fossil fuels. Desirability lies in the development of efficient, economically viable and sustainable catalysts for this approach. Many recent publications describe the successful utilization of eutectic solvents/deep eutectic solvents for the synthesis of cyclic carbonates. Nevertheless, the majority of them focuses on reporting catalyst performance (product yield) and reaction conditions (temperature, pressure, reaction time) with little insights into the sustainability aspects (process mass intensity (PMI), solvents, and critical elements involved, as well as health and safety parameters described by H-code). Taking an example of the system composed of naturally occurring, inexpensive tannic acid combined with choline halides, the green chemistry metrics were evaluated for different DESs and other two-component catalysts and discussed in terms of guiding future designs of sustainable catalytic systems for the synthesis of cyclic carbonates.