Densities, Viscosities, Speeds of Sound, Bulk Moduli, Surface Tensions, and Flash Points of Binary Mixtures of Ethylcyclohexane or Methylcyclohexane with <i>n-</i>Dodecane or <i>n-</i>Hexadecane at 0.1 MPa

This work reports physical property measurements of binary mixtures of ethylcyclohexane or methylcyclohexane with either <i>n-</i>dodecane or <i>n-</i>hexadecane at temperatures ranging from (293.15 to 333.15) K. Mixture densities fell between those of the pure components. All excess molar volumes were positive, indicating less efficient packing in the mixture systems. Mixture speeds of sound fell between those of the pure components, except in ethylcyclohexane in <i>n-</i>dodecane mixtures where increasing the mole fraction of ethylcyclohexane caused the speed of sound to decrease to a minimum before increasing again. Speed of sound deviations for ethylcyclohexane/<i>n-</i>hexadecane and methylcyclohexane/<i>n-</i>dodecane mixtures were not statistically different from zero, while they were positive for methylcyclohexane/<i>n-</i>hexadecane mixtures and negative for ethylcyclohexane/<i>n-</i>dodecane mixtures. Both volume expansion and compressibility influence these deviations. For all mixtures, increasing alkylcyclohexane concentrations caused the viscosity to decrease. Excess free energies of activation for viscous flow were not statistically different from zero for the mixtures studied, indicating that these mixtures were behaving ideally. Mixture surface tensions and flash points fell between the values for the pure components. Comparison of these physical properties with those of petroleum-based fuels show that ethylcyclohexane/<i>n-</i>hexadecane mixtures had properties that best matched those of jet fuel