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 ( V ϕ 0 $V_{\varphi }^0$ ) and experimental slopes ( A v ) 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.