Viscosity and surface tension of binary systems of N,N-dimethylformamide with alkan-1-ols at different temperatures

Viscosity eta and surface tension sigma were measured for binary mixtures of N,N-dimethylformamide DMF with pentan-1-ol, hexan-1-ol, and heptan-1-ol at T = (298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure over the entire mole fraction range. Deviations in viscosity Delta eta and surface tension Delta sigma were calculated using experimental results. Moreover, the values of the excess Gibbs free energy of activation G*(E), surface enthalpy H-sigma and surface entropy S-sigma of these mixtures were determined. Viscosity measurements of the binary systems were correlated with Grunberg and Nissan, the three-body and four-body McAllister expressions. Viscosity deviation, surface tension deviation and excess Gibbs energy of activation functions were fitted to the method of Redlich-Kister (R-K) polynomial to estimate the coefficients and standard deviations. The effects of chain length of alkan-1-ols and temperature on the thermodynamic properties of binary systems were studied. (C) 2012 Elsevier Ltd. All rights reserved.