Halide-free deep eutectic solvents constructed from natural compounds for converting carbon dioxide to cyclic carbonate.

Halide-free deep eutectic solvents (DESs) derived from natural biological compounds were used to gently catalyze the cycloaddition reaction between CO2 and epoxides, with a TOF of 645 h-1. The DFT calculation result was in good agreement with the experiment result, indicating that the ring closure process was the rate-determining step.