Basic ionic liquids. A short review

Basic ionic liquids as environmental-friendly solvents and catalysts with high activity and selectivity and easily recovered materials were used to replace traditional bases such as KOH, NaOH, K₂CO₃, NaHCO₃, NaOAc, triethylamine, or tetrabutylammonium acetate. Using the traditional bases generally suffered from disadvantages such as waste production, corrosion and environmental problems. Basic ionic liquids offering a new possibility for developing environmentally friendly basic catalysts due to the combination of the advantages of inorganic bases and ionic liquids. They are flexible, nonvolatile,noncorrosive, and immiscible with many organic solvents. Basic ionic liquids (BILs) have been used in base-catalyzed processes such as Michael addition, Markovnikov addition, Knoevenagel condensation, Henry reaction, Mannich reaction, oximation, Feist-Benary reaction and etc. In this short review, we wish to present an overview of the types, properties, synthesis and applications of basic ionic liquids.