Easily available and inexpensive FeIII carbamates were employed in the solvent-free synthesis of a series of cyclic carbonates from epoxides and CO2 at room temperature and atmospheric pressure, in the presence of a cocatalyst. Different experimental conditions (type and concentration of catalyst and cocatalyst, as well as reaction time) were investigated: Fe(O2 CNEt2 )3 and NBu4 Br acted as the best catalyst/cocatalyst combination, allowing the formation of propylene carbonate and 1,2-butylene carbonate with quantitative yield and selectivity in 24 h. According to NMR and DFT studies, the reaction proceeds with the dynamic trapping of carbon dioxide as a carbamato ligand.
Keywords: carbon dioxide; cyclic carbonates; epoxides; homogeneous catalysis; iron.
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.