Densities, Speeds of Sound, and Isentropic Compressibilities for Binary Mixtures of 2-Ethyl-1-hexanol with 1-Pentanol, 1-Heptanol, or 1-Nonanol at the Temperature 298.15 K

Abstract

Densities and speeds of sound for binary mixtures of 2-ethyl-1-hexanol with 1-pentanol, 1-heptanol, or 1-nonanol were measured over the entire composition range at the temperature 298.15 K by means of a vibrating tube densimeter and the pulse-echo-overlap method. Also, the densities for pure compounds in the temperature range from (288.15 to 318.15) K were measured. From experimental data, the excess molar volumes and excess molar isentropic compressibilities were calculated. The deviations of the speeds of sound were calculated as well. The Redlich−Kister polynomials were fitted to the results, and smooth representations of the results are presented. For the mixtures studied, the negative values of the excess molar isentropic compressibilities over the entire composition range are observed. The values of the excess molar volumes are negative over the entire composition range for mixtures of 2-ethyl-1-hexanol with 1-pentanol or 1-heptanol. For the mixtures of 2-ethyl-1-hexanol with 1-nonanol, the excess molar volume is slightly s-shaped; that is, the close zero or positive values in the 1-nonanol rich region are observed. The excesses are more negative as the carbon chain length of the 1-alkanol is shorter. The isobaric coefficients of thermal expansion for pure compounds were calculated by analytical differentiation of the density dependence on the temperature.