Yongya Zhang

DBU and DBU-Derived Ionic Liquid Synergistic Catalysts for the Conversion of Carbon Dioxide/Carbon Disulfide to 3-Aryl-2-oxazolidinones/[1,3]Dithiolan-2-ylidenephenyl- amine†

An intermolecular synergistic catalytic combination of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) and a DBU‐derived bromide ionic liquid has been developed for the conversion of CO2, epoxides, and amines under metal‐ and solvent‐free conditions. Various 3‐aryl‐2‐oxazolidinones are produced in moderate to excellent yields within a short reaction time. NMR spectroscopy and DFT calculations demonstrate that DBU as a hydrogen bond acceptor and the ionic liquid as a hydrogen bond donor activate the substrates cooperatively by inducing hydrogen bonds to promote the reaction effectively. Based on these results, a possible reaction mechanism on the synergistic catalysis of DBU and the ionic liquid is proposed. In addition, the reaction of CS2, ethylene oxide, and aniline catalyzed by the combination of DBU and the DBU‐derived ionic liquid also proceeds smoothly, which opens a hitherto unreported route to [1,3]dithiolan‐2‐ylidenephenylamine in a straightforward way.

Water-enriched poly(ionic liquid)s: highly-efficient microreactors for the hydrolysis of ethylene carbonate

Poly(ionic liquid) (PIL) catalysts with swelling ability and water enrichment ability in water/ethylene carbonate (EC) mixed substrates were designed and synthesized via a one-step direct radical copolymerization of N-vinylimidazolium IL monomers, sodium acrylate and crosslinkers. The structure and morphology of the PILs were characterized by NMR, FT-IR, TGA, SEM and elemental analysis. The effect of substituent groups and crosslinkers on the swelling ability and water enrichment ability of PILs in water and EC was studied. The water enrichment ability of PILs was positively related to the hydrophilicity of 3-substituents on imidazoliums and the crosslinkers, and water could be absorbed inside quantitatively. These PIL catalysts could enrich the optimal ratio of water to EC inside and act as high-efficiency microreactors for the catalytic hydrolysis of EC. The water enrichment ability of PIL microreactors was helpful for the decrease of water amount and the increase of catalytic efficiency.