Nine salts, expected to be protic ionic liquids, have been synthesized by a direct reaction of proton transfer from a number of protic acids to methyl- or butyl-imidazole. The temperatures of phase transitions and thermal stability of the PILs have been measured. Physico-chemical properties of the ionic liquids, such as conductivity, electrochemical stability, viscosity, density have been measured and discussed, and the PILs ionicity has been analyzed on the basis of the Walden plots.
