In this paper we have carried out molecular dynamics simulations (MD) for model systems of liquid n-alkane oligomers ($C_{12}{sim}C_{80}$) at high temperatures (~2300 K) in a canonical ensemble to calculate viscosity ${eta}$, self-diffusion constants D, and monomeric friction constant ${zeta}$. We found that the long chains of these n-alkanes at high temperatures show an abnormality in density and in monomeric friction constant. The behavior of both activation energies, $E_{eta}$ and $E_D$, and the mass and temperature dependence of ${eta}$, D, and ${zeta}$ are discussed.