Densities and Viscosities at 293.15–373.15 K, Speeds of Sound and Bulk Moduli at 293.15–333.15 K, Surface Tensions, and Flash Points of Binary Mixtures of <i>n</i>‑Hexadecane and Alkylbenzenes at 0.1 MPa

The viscosities and densities (293.15–373.15 K), speeds of sound (293.15–333.15 K), surface tensions (room temperature), and flash points were measured for binary mixtures of <i>n</i>-hexadecane and alkylbenzenes (hexylbenzene, octylbenzene, dodecylbenzene), which are components of diesel fuel. Increasing the temperature decreased densities, and excess molar volumes of mixtures were higher for hexylbenzene mixtures than for octylbenzene mixtures and insignificantly different from zero for dodecylbenzene mixtures. The decrease in excess molar volume with increasing alkyl chain length is consistent with other binary mixtures of <i>n</i>-hexadecane and alkylbenzenes. Increasing the temperature decreased viscosities, and the McAllister three-body model successfully modeled viscosity with the compound in the mixture with the highest individual viscosity having the largest fitted interaction parameter. Mixture flashpoints, speed of sounds, bulk moduli, and surface tensions fell between the pure component values. For <i>n</i>-hexadecane/<i>n</i>-hexylbenzene mixtures, as the mole fraction of hexylbenzene increased, the speed of sound remained constant until a mole fraction of 0.5; then the speed of sound increased. On the basis of these data, binary mixtures of these compounds could be formulated to have property values that match those found in diesel fuel, except for surface tension, and thereby be potential fuel surrogates