Dodecane and n -Alkylbenzene Binary Mixtures: Densities, Speeds of Sound, and Viscosities within the Range of 288.15 to 333.15 K and at 0.1 MPa

Abstract

Physical processes and properties are important for modeling combustion behavior and designing surrogate mixtures to model real fuels. This work reports densities, speeds of sound, and viscosities of mixtures of dodecane with n-alkylbenzenes, which can aid in these modeling and design efforts. These properties increased with decreasing temperature and increasing amounts of the component with the higher property value, except for n-octylbenzene’s viscosities and ethylbenzene’s and n-propylbenzene’s speeds of sound, where a mixture had the lowest value. Some mixture viscosities and densities fell within fuel specifications, and their range values for bulk moduli are large enough to possibly exhibit differences in injection behavior in an engine. Increasing the size of n-alkylbenzene caused the VmE’s and KsE’s to decrease, the cE’s to increase, and the Δη’s to decline to a minimum before increasing again. The minimum was found in a mixture with n-hexylbenzene. VmE were successfully modeled using the Prigogine–Flory–Patterson (PFP) Model, which showed a positive interactional term for all mixtures (indicating weaker interactions in the mixtures than for pure components), demonstrating the differences in structure, which decreased with n-alkylbenzene size. Negative free volume and pressure terms were found for larger n-alkylbenzenes and produced overall negative VmE’s values.