Thermophysical properties of binary mixtures of triethoxysilane, methyltriethoxysilane, vinyltriethoxysilane and 3-mercaptopropyltriethoxysilane with ethylbenzene at various temperatures

• Values of ρ and nD of binary mixtures containing organosilicon compounds at different temperatures were measured.
• α  , VmE, V¯iE,∞, (n2)E, Rm and ΔRm were studied.
• The excess molar volumes, excess squared refraction indices and the deviations in molar refractions were negative.

The density and refractive index were determined for binary mixtures of triethoxysilane, methyltriethoxysilane, vinyltriethoxysilane and 3-mercaptopropyltriethoxysilane with ethylbenzene at different temperatures (T = 288.15, 298.15, 308.15, 318.15 and 328.15 K) and atmospheric pressure using a DMA4500&RXA170 combined system. The excess molar volume (VmE), partial excess volume at infinite dilution (V¯iE,∞), isobaric coefficient of thermal expansion (α), excess squared refraction indices [(n2)E], Lorentz–Lorenz molar refraction (Rm) and the deviation in molar refraction (ΔRm) have been calculated using this data. The results have been incorporated into the Redlich–Kister equation and used to estimate the binary interaction parameter and standard deviation. In addition, the excess molar volume (VmE) was calculated and correlated using the Legendre polynomials. The value of partial excess volume at infinite dilution (V¯iE,∞) for these binary systems at different temperatures was calculated from either the adjustable parameters of Redlich–Kister smoothing equation or the Legendre polynomials. The isobaric coefficient of thermal expansion (α) of the binary systems was estimated using the temperature dependence of the densities. The results indicate that the excess molar volumes, excess squared refraction indices and the deviations in molar refractions at each temperature were negative. These phenomena are a result of a number of factors including: the partial interstitial accommodation effect, disruption in the orientational order of the pure components and steric structure.

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