Basic ionic liquids for catalysis: the road to greater stability

Basic ionic liquids can replace organic or inorganic bases in a wide range of reactions. In this minireview the synthesis of homogeneous and heterogeneous basic ionic liquids and their applications in catalysis are discussed. The dual properties of tuneability and wide spectrum solubility make basic ionic liquids unique amongst bases. Acidic ionic liquids have been applied in large scale industrial processes, but in contrast the application of basic ionic liquids has been hampered by ion instability. This problem is now surmountable and strategies for stabilising ionic liquids within basic solutions have been developed that are molecular and material in basis. The review investigates the potential to apply these stabilised basic ionic liquids as catalysts, emphasising facile recovery from the reaction mixture. Homogeneous and heterogenized basic ionic liquids as reaction catalysts have been highlighted, particularly where they are used to promote reactions that could form the basis of more sustainable energy and chemical production.