Synthesis and Physical Properties of Tunable Aryl Alkyl Ionic Liquids (TAAILs)

Tunable aryl alkyl ionic liquids (TAAILs) based on the imidazolium cation were first reported in 2009. Since then, a series of TAAILs with different properties due to the electron-donating or -withdrawing effect of the substituents at the aryl ring has been developed. Herein, a wide variety of those ionic liquids (ILs) is presented in terms of their cation structure. The authors synthesized ILs containing the bromide or bis(trifluoromethane)sulfonimide anion and 1-aryl-3-alkyl imidazolium cations with various substituents in the ortho and/ or para position of the phenyl ring and alkyl chains of different lengths varying from butyl to dodecyl. The differences of their physical properties (melting point, thermal decomposition, viscosity, electro-chemical window) of these ILs are reported according to their structure.