1-Alkyl-3-methylimidazolium alkanesulfonate ionic liquids, [CnH2n+1mim][CkH2k+1SO3]: synthesis and physicochemical properties

Abstract

A set of 1-alkyl-3-methylimidazolium alkanesulfonate ionic liquids, [C_nmim][C_kSO₃], formed by the variation of the alkyl chain lengths both in the cation and the anion (n = 1–6, 8, or 10; k = 1–4, or 6), was synthesised, with sixteen of them being novel. The ionic liquids were characterised by ¹H and ¹³C NMR spectroscopy, and mass spectrometry. Their viscosities and densities as a function of temperature, as well as melting points and decomposition temperatures, were determined. The molecular volumes, both experimental and calculated, were found to depend linearly on the sum (n + k).