Abstract: An improved procedure was developed for the synthesis of 1-benzyl-3-alkylbenzotriazolium ionic liquids from commercially available starting materials. The structures of target compounds were characterized by FT-IR, 1H NMR and 13C NMR. The yield reaches 82.7%~86.1% when the molar ratio of substituted alkyl benzotriazole to cuprous iodide and benzyl bromide is 10∶2.5∶11, and the reaction time is 5~6 h. Moreover, their solubility, the relationship between molecular structure and melting point of the ionic liquids were investigated.

Key words: benzotriazolium ionic liquids, catalysis, synthesis, characterization