Study of preparation and thermal stability of cyano-functionalized imidazolium type ionic liquids

Abstract

Sixteen imidazolium type cyano-functionalized Brønsted acidic ionic liquids with HSO4- and H2PO4- anion were prepared adopting twostep method and were characterized by FT-IR, 1H and 13C NMR. The onset temperatures of thermal decomposition of the ionic liquids were measured using thermogravimetric analysis. It was found that the decomposition onset temperatures of the as-synthesized ionic liquids were in the range of 200-260 °C. Additionally, the decomposition temperatures were highly dependent on the nature of the anions. Thermal stability of these cyano-functionalized ionic liquids decreased in the order of HSO 4- > H2PO4-.