Due to their unique properties, ionic liquids have offered great potential for developing clean catalytic technologies. After a short introduction of their advantages in green catalysis, recent advances in ionic liquid catalysis are reviewed with emphasis on four hot fields, viz. biomass conversion in ionic liquids, catalytic production of fine chemicals in ionic liquids, supported ionic liquid phase catalysis, as well as Friedel–Crafts reactions in ionic liquids. In particular, through selected samples, we show here the advantages and potential of ionic liquids in exploring cleaner catalytic technologies, as compared to traditional catalytic processes. Finally, further development of ILs in catalysis is briefly prospected.
This paper reports an effective route for the syntheses of N-substituted dicarbamates from dialkyl carbonates and polyurea derivatives, in which polyurea derivatives could be successfully synthesized from aliphatic diamines and CO2 in the absence of any catalyst. Under the optimized reaction conditions, various N-substituted carbamates were successfully synthesized with 93–98% isolated yields over a MgO–ZnO catalyst. The catalyst could be reused for several runs without deactivation. The catalysts were characterized with X-ray photoelectron spectroscopy, X-ray diffraction and temperature-programmed desorption.