Densities, Viscosities, and Speeds of Sound of n-Tetradecane and n-Alkylcyclohexane Binary Mixtures within the Temperature Range (288.15-333.15) K

This work reports on the densities, viscosities, and speeds of sound of 2-component mixtures of n-tetradecane and n-alkylcyclohexanes (methyl-, ethyl-, propyl-, butyl-, pentyl, hexyl-, heptyl-, octyl-, decyl-, and dodecylcyclohexane) at select temperatures between 288.15 and 333.15 K and pressure of 0.1 MPa. Decreases in mixture densities, viscosities, and speeds of sound were found with increases in temperature and in the component with the lower property value, except for the speeds of sound of n-butylcyclohexane mixtures in which the equimolar mixture had a speed of sound lower than the individual component values. Lengthening the alkyl chain on the n-alkylcyclohexanes (1) decreased the mixture excess molar volumes (VmE), (2) decreased the excess speeds of sound (cE's) and viscosity deviations (Delta.) until minimums were reached after which the cE's and..'s increased, and (3) increased the excess isentropic compressibilities (KsE's) until a maximum was reached after which it decreased. For all alkylcyclohexanes tested, except methylcyclohexane, VmE 's and KsE's had the same sign, suggesting that the changes in the volume occupied by the molecules influence the mixture compressibility. In contrast, methylcyclohexane had the largest positive VmE but a negative KsE, which indicates that the expanded volume was not more compressible. Most of VmE 's, cE's, and..'s of n-tetradecane mixtures fell between those reported for n-tridecane and n-hexadecane. n-Tetradecane could be used in fuel surrogates where larger density, viscosity, and speeds of sound are needed to emulate the real fuel.