Ionic Parachor and Its Application in Acetic Acid Ionic Liquid Homologue 1-Alkyl-3-methylimidazolium Acetate {[C_<i>n</i>mim][OAc](<i>n</i> = 2,3,4,5,6)}

Five acetic acid ionic liquids (AcAILs) [C_<i>n</i>mim][OAc](<i>n</i> = 2,3,4,5,6) (1-alkyl-3-methylimidazolium acetate) were prepared by the neutralization method and characterized by ¹HNMR spectroscopy and differential scanning calorimetry (DSC). The values of their density and surface tension were measured at 298.15 ± 0.05 K. Since the AcAILs can strongly form hydrogen bonds with water, the small amounts of water are difficult to remove from the AcAILs by common methods. In order to eliminate the effect of the trace water, the standard addition method (SAM) was applied to these measurements. As a new concept, ionic parachor was put forward. [OAc]⁻ was seen as a reference ion, and its individual value of ionic parachor was determined in terms of two extrathermodynamic assumptions. Then, the values of ionic parachors of a number of anions, [NTf₂]⁻, [Ala]⁻, [AlCl₄]⁻, and [GaCl₄]⁻, were obtained by using the value of the ionic parachor of the reference ion; the parachor and surface tension of the investigated ionic liquids in literature were estimated. In comparison, the estimated values correlate quite well with their matching experimental values

Physicochemical Properties of Air and Water Stable Rhenium Ionic Liquids

Air and water stable ionic liquids (ILs) based on catalytic functional metal rhenium, [C_<i>n</i>mim]­[ReO₄]­(<i>n</i> = 2,4,5,6)­(1-alkyl-3-methylimidazolium perrhenate), are designed and synthesized. Their density and surface tension are measured in the temperature range of 293.15–343.15 ± 0.05 K. Some physical-chemical properties of the ILs have been calculated or estimated by the empirical methods. The ion parachor is put forward and calculated by two extrathermodynamic assumptions. According to the interstice model, the thermal expansion coefficient of ILs [C_<i>n</i>mim]­[ReO₄], α, are calculated and in comparison with experimental values, their magnitude order is in good agreement