Temperature effects on the viscosity and the wavelength-dependent refractive index of imidazolium-based ionic liquids with a phosphorus-containing anion

Abstract

A systematic study on the viscosity and refractive index of 1-alkyl-3-methylimidazolium based ionic liquids (alkyl = methyl, butyl and hexyl) combined with three phosphorus containing anions, i.e. dimethylphosphate, methyl methylphosphonate and methylphosphonate, is reported. Experimental measurements account for temperature effects, while the refractive index is determined at multiple wavelengths in the visible and near infrared region. Despite the structural similarity of these anions, significant differences in the physical properties of the resulting ILs are identified, along with the clear trend of viscosity increase - and refractive index decrease - with increasing alkyl chain length on the cation. Ab initio theoretical calculations are carried out to support and rationalise the observed behaviour.

Chiral Biobased Ionic Liquids with Cations or Anions including Bile Acid Building Blocks as Chiral Selectors in Voltammetry

“…[36][37][38] Despite these interesting characteristics, CILs obtained from deoxycholic acid, and also from other bile acids, are to the best of our knowledge not reported in the literature. Thus, the longstanding experience of some of us in the field of the ionic liquids [39][40][41][42][43] and in the use of bile acids in chemical enantiodiscrimination processes [44][45][46][47][48][49][50][51] suggested the synthesis of new CILs starting from deoxycholic acid (Figure 1). To this aim, the carboxylic group was converted in a good leaving group for the nucleophilic displacement with 1-methylimidazole to obtain CILs having the chiral steroidal cation, or underwent a neutralization reaction to obtain CILs having the steroidal anion.…”

“…Despite these interesting characteristics, CILs obtained from deoxycholic acid, and also from other bile acids, are to the best of our knowledge not reported in the literature. Thus, the longstanding experience of some of us in the field of the ionic liquids [39–43] and in the use of bile acids in chemical enantiodiscrimination processes [44–51] suggested the synthesis of new CILs starting from deoxycholic acid (Figure 1).…”

Influence of the Use of an Ionic Liquid as Pre-Hydrodistillation Maceration Medium on the Composition and Yield of Cannabis sativa L. Essential Oil

“…1,3-Dimethyl-1H-imidazol-3-ium dimethylphosphate ([DMIM]DMP) was obtained following the general procedure previously reported for dimethylphosphate ionic liquids [ 47 ]. 1-Methylimidazole (1 equiv.)…”

Insight into the Liquid–Liquid Extraction System AuCl4−/HCl/A327H+Cl− Ionic Liquid/Toluene

“…The organic extractants used in liquid-liquid extraction include ionic liquids, which have attracted further interest due to their inherent properties [13][14][15][16], including high selectivity and conductivity [17], negligible vapor pressure and low volatility [18], inflammability or low flammability [19], strong thermal stability [20], high refractive index [21], and solvation power of organic and inorganic compounds [22,23]. Due to these properties, these liquids are considered to be green solvents.…”