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Density, viscosity and refractive index of the dimethyl sulfoxide + o-xylene system

Ciocirlan Oana (Department of Applied Physical Chemistry and Electrochemistry, Faculty of Industrial Chemistry, 'Politehnica' University of Bucharest, Splaiul Independentei, Romania)
Iulian Olga (Department of Applied Physical Chemistry and Electrochemistry, Faculty of Industrial Chemistry, 'Politehnica' University of Bucharest, Splaiul Independentei, Romania)

This work reports the experimental results of the densities, viscosities and refractive indices between 298.15 and 323.15 K of the dimethyl sulfoxide + o-xylene system over the entire composition range of the mixtures. The excess molar volumes (VE), viscosity deviations (Δv), excess Gibbs energy of activation of viscous flow (G*E) and deviations in the refraction (ΔR) were calculated from the experimental data; all the computed quantities were fitted to the Redlich-Kister equation. The system exhibits moderate negative values for the investigated excess properties. The resulting excess functions were interpreted in structural and interactional terms. From the experimental data, the thermodynamic functions of the activation of viscous flow were estimated. The viscosity data were correlated with several semi-empirical equations. The two-parameter McAllister equation can give very good results.

Keywords: dimethyl sulfoxide, o-xylene, density, viscosity, excess properties