First volatility study of the 1-alkylpyridinium based ionic liquids by Knudsen effusion

For the first time, a volatility study of the 1-ethylpyridinium bis(trifluoromethylsulfonyl)imide ([C2Py][NTf2], CAS: 712354-97-7), 1-propylpyridinium bis(trifluoromethylsulfonyl)imide ([C3Py][NTf2]) and 1-butylpyridinium bis(trifluoromethylsulfonyl)imide ([C4Py][NTf2], CAS: 187863-42-9) ionic liquids, is presented. The vapor pressures as a function of temperature, for this ionic liquids were measured and the thermodynamic properties of vaporization were derived. The analysis and rationalization of the obtained results for the alkylpyridinium based ionic liquids was done based on the comparison with the [CN-1C1im][NTf2] (N = 3–5). The volatility of pyridinium is five times lower than the imidazolium based ionic liquids and that is driven by their higher enthalpy of vaporization.