Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C3, C5–C7, and C9–C10 have been measured by the transpiration method. The molar enthalpies of vaporization ΔlgHm of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization ΔlgHm (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

► We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. ► Variations on the alkyl chain length n were C3, C5–C7, and C9–C10. ► Enthalpies of vaporization were derived from (p, T) dependencies. ► Enthalpies of vaporization at 298.15 K were linear dependent on the chain length.