The mixing properties, IR analysis and quantum chemical calculations of trimethoxylsilane derivatives with ethanol, 1-butanol, 1-pentanol and 1-octanol

Abstract

The density, viscosity and speed of sound of trimethoxylsilane derivatives with ethanol, 1-butanol, 1-pentanol and 1-octanol have been measured at 298.15, 303.15, 308.15, 313.15 K, 318.15 and 323.15 K, respectively. The excess molar volume, viscosity deviation, excess Gibbs energy of activation of viscous flow, isobaric thermal expansivity and isentropic compressibility deviation were calculated from these results. The Redlich–Kister equation was used for the correlation. The calculated excess properties have been discussed according to the possible interactions formed between the molecules in the mixture using equimolar attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. In all of the compositions and experimental temperature ranges studied, the excess molar volumes were found to be negative for vinyl trimethoxy silane and phenyl trimethoxy silane with ethanol. This may be attributed to the close accumulation of molecules and easier formation of cross-association structures between the alkoxysilane molecules. However, the excess molar volume of the binary mixture of vinyl trimethoxy silane and phenyl trimethoxy silane with n-butanol, n-pentanol, and n-octanol was positive. Hydrogen bond fracture may play a leading role in this process. The excess molar volumes of the binary system comprised of trifluoropropyl trimethoxy silane with ethanol and 1-octanol were all positive. This may be attributed to the influence of steric hindrance, which makes it difficult for trifluoropropyl trimethoxy silane to form a cross-association structure with alcohol molecules.