Densities and Viscosities for Four Binary Systems of Tetrahydrotricyclopentadiene with <i>n</i>-Dodecane, Methylcyclohexane, Decalin, or 1,2,3,4-Tetrahydronaphthalene at <i>T</i> = (293.15 to 343.15) K

In order to achieve a comprehensive understanding of the properties of tetrahydrotricyclopentadiene (THTCPD) as a potential candidate for high-energy-density hydrocarbon fuels, the density and viscosity of binary mixtures comprising THTCPD and four representative hydrocarbons─n-dodecane, methylcyclohexane, decalin, and 1,2,3,4-tetrahydronaphthalene─were experimentally determined under conditions of T = (293.15 to 343.15) K and atmospheric pressure p = 0.1 MPa. At a constant temperature, both density and viscosity exhibited continuous increases with the rising molar fraction of THTCPD in the binary systems. Furthermore, the excess molar volume (VmE) and viscosity deviation (Δη) of these binary systems were calculated and subsequently fitted by using the Redlich–Kister equation. With the exception of the THTCPD + 1,2,3,4-tetrahydronaphthalene system, the VmE values for all other systems were negative, with their absolute values increasing as the temperature rose. The Δη values for all systems were also negative, and their absolute values decreased significantly with increasing temperature. These findings are interpreted in terms of intermolecular interactions and structural effects, providing critical reference data for the development of high-energy-density hydrocarbon fuels.