Efficiency of DBU/iodine cooperative dual catalysis for the solvent-free synthesis of five-membered cyclic carbonates under atmospheric CO2 pressure

•5-Membered cyclic carbonates were prepared from various oxiranes.•The catalysis used is based on an organo-based bifunctional system.•The carboxylation was done at both low temperature and pressure in CO2.

The DBU·I2 dual catalyst is shown to have a very high activity for the coupling reaction of CO2 and various (bis)oxiranes. The cooperative work of both DBU and iodine is tolerant to water and allows performing the cyclo-addition of carbon dioxide in very mild conditions of pressure (pCO2 = 1 bar) and in total absence of organic solvent.

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