Undecane and n-Alkylcyclohexanes Binary Mixtures: Densities and Speeds of Sound between 288.15 and 333.15 K and Viscosities between 293.15 and 323.15 K at 0.1 MPa

The densities, dynamic viscosities, and speeds of the sound of mixtures of undecane with n-alkylcyclohexanes (methyl-, ethyl-, propyl-, butyl-, pentyl-, hexyl-, nonyl-, decyl-, and dodecylcyclohexane) were measured between 288.15 and 333.15 K and 0.1 MPa. Increasing temperature decreased the density, viscosity, and speed of sound. Increasing the concentration of components with higher property values produced mixtures with higher property values for most systems. Excess molar volumes (V(m)(E')s) ranged from -0.33 to 0.17 m(3)center dot mol(-1). For equimolar mixtures, the V(m)(E')s decreased as the n-alkyl chain length increased. Viscosity deviations based on a log-linear relationship (Delta eta's) ranged from -0.04 to 0.22 mPa<middle dot>s. The n-hexylcyclohexane mixtures produced the smallest Delta eta's. Excess speeds of sound (c(E')s) ranged from -3.3 to 12.4 m<middle dot>s(-1) and excess isentropic compressibilities (K(s)(E')s) varied from -13.8 to 2.7 TPa-1. Ethylcyclohexane mixtures produced the smallest cE values and the largest K-s(E'). The V(m)(E')s and K(s)(E')s for most mixtures were the same sign, thereby suggesting that the deviations in the volume occupied by the molecule affected the mixture compressibility. These data provide information to researchers who are seeking alternative mixtures to represent fuels and those looking at the impact of blendstock material on fuel behavior and molecular interactions.