Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Selected Ternary Mixtures of n-Butylcyclohexane + a Linear Alkane (n-Hexadcane or n-Dodecane) + an Aromatic Compound (Toluene, n-Butylbenzene, or n-Hexylbenzene)

Researchers seek to understand the combustion of petroleum fuel, which contains hundreds of compounds, by studying properties and oxidation behavior of less complex mixtures (surrogates) containing fuel components. In this study, viscosities and densities (293.15 to 343.15 K), speeds of sound (293.15 to 333.15 K), surface tensions (∼314 K) and flash points were measured for ternary mixtures of representative fuel components: n-alkanes, aromatic compounds, and n-butylcyclohexane. Mixture surface tensions and flashpoints fell between the pure component values. The speeds of sound for ternary mixtures containing n-dodecane and n-butylcyclohexane increased with increasing aromatic compound concentration. As the aromatic compound concentration in mixtures with n--hexadecane and n--butylcyclohexane increased, the mixtures’ speeds of sound remained level or decreased to a minimum before increasing to the value of the aromatic compound. The isentropic bulk moduli increased with increasing aromatic compound concentration, except for toluene for which a minimum was found. Excess molar volumes were positive, viscosity deviations were negative, and a McAllister three-body equation successfully modeled viscosity. Positive excess molar volumes and negative dynamic viscosities suggest that dispersion forces dominate the molecular interactions in these mixtures.