Density, viscosity, refractive index and conductivity of switchable hydrophilicity solvent systems: N,N-Dimethylbenzylamine, water and carbon dioxide

Density, viscosity, refractive index and conductivity of switchable hydrophilicity solvent (SHS) systems (N,N-dimethylbenzylamine (BDMA), water, and carbon dioxide) were measured as a function of molality of BDMAH-bicarbonate salt for the SHS system at temperatures from (283.15-308.15) K. Three empirical equations were successfully applied to correlate the density, viscosity, refractive index, and electrical conductivity of the SHS systems with temperature and BDMAH-bicarbonate salt concentration. From these experimental results, apparent molar volume, limiting partial molar volume, the relative viscosity and viscosity B-coefficients were calculated. The limiting apparent molar volumes (Vϕ0) and experimental slopes (Av) derived from the Redlich-Mayer type equation have been interpreted in terms of solute-solute and solute-solvent interactions. In terms of Jones-Dole equation, the viscosity B-coefficients with large positive value and dB/dT < 0 were obtained and these facts implied that the BDMAH-bicarbonate salt is water-structure-making.