A general and direct synthesis of imidazolium ionic liquids using orthoesters

A general method to synthesize halide and halide-free ionic liquids was developed. Direct alkylation of imidazole and pyridine derivatives was performed in the presence of an acid using an orthoester as the alkyl donor yielding ionic liquid products. Residual Cl and water contents of the ionic liquids were determined by ion chromatography and a Karl-Fisher test.