Volumetric, viscosimetric and surface properties of aqueous solutions of triethylene glycol, tetraethylene glycol, and tetraethylene glycol dimethyl ether

Densities (rho) and viscosities (eta) for water (W) + triethylene glycol (TrEG), W + tetraethylene glycol (TeEG), and W + tetraethylene glycol dimethyl ether (TeEGDME) were measured for the whole range of composition at five different temperatures ranging from 303.15 K to 323.15 K. Surface tensions for these systems were measured at 303.15 K for different mole fractions. The excess molar volumes, V-m(E), and excess viscosities, (eta(E)), were calculated from measured parameters. Derived volumetric and viscosimetric properties were fitted to Redlich-Kister type equation. The properties were found to change significantly with increasing the number of glycol units and to be greatly affected by methyl substitution within the glycol unit. For unsubstituted glycols a gradual increase in density and viscosity was observed on increasing the concentration, whereas for the methyl-substituted glycol TeEGDME sharp maxima were apparent in the density-composition and viscosity-composition curves. The surface tensions of aqueous solutions of methyl-substituted glycol TeEGDME were found to be significantly lower than other aqueous glycols. (C) 2012 Elsevier B.V. All rights reserved.