Apparent molar volumes and isentropic compressions of benzylalkylammonium ionic liquids in dimethylsulfoxide from 293.15 K to 328.15 K

• Density and speed of sound measured for binary mixtures of ionic liquid and DMSO.
• Apparent molar volumes were correlated with Redlich–Mayer type equation.
• Limiting apparent molar isentropic compression values are positive.
• Intermolecular interactions between studied ionic liquids and DMSO were analyzed.

Densities, ρ and speeds of sound, u of four benzylalkylammonium ionic liquids (ILs), namely, benzylmethylammonium propionate (BMAP), benzylmethylammonium hexanoate (BMAH), benzyldimethylammonium propionate (BDMAP) and benzyldimethylammonium hexanoate (BDMAH) with dimethylsulfoxide (DMSO) have been determined as a function of ILs concentration, ranging from (0.1 to 0.8) mol kg−1, at temperatures from 293.15 K to 328.15 K with 5 K interval and at atmospheric pressure. The apparent molar volumes, Vm, apparent molar isentropic compression, Ks,m and limiting apparent molar expansion, Em∞ of the ILs have been calculated from the experimental density and speed of sound data. The Redlich–Mayer type of equation was fitted to the apparent molar volume and apparent molar isentropic compression data, to evaluate apparent molar volume at infinite dilution Vm∞ and apparent molar isentropic compression, Km∞ at infinite dilution.

Figure optionsDownload as PowerPoint slide BDMAH (benzyldimethylammonium hexanoate) in DMSO solutions.Comparison of apparent molar expansion at infinite solution, Em∞ as a function of temperature, T forFigure optionsDownload as PowerPoint slideBDMAP (benzyldimethylammonium propionate),Figure optionsDownload as PowerPoint slide