Am. Demiriz et al., THE VIRIAL-COEFFICIENTS AND THE EQUATION OF STATE BEHAVIOR OF THE POLAR COMPONENTS CHLORODIFLUOROMETHANE, FLUOROMETHANE AND ETHANENITRILE, Fluid phase equilibria, 85, 1993, pp. 313-333
Burnett p,rho,T measurements are reported for chlorodifluoromethane, f
luoromethane and ethanenitrile. Some isochoric data on fluoromethane a
re added. Literature data on fluoromethane are also used. It is shown
that the virial coefficients of these polar molecules depend on the fo
urth power of the reduced dipole moment, a much more dramatic dependen
ce than that of the cohesive energy of the liquid. The second virial c
oefficient becomes much more negative and the third much more positive
compared with those of non-polar molecules. The fourth, which can be
neglected for non-polar molecules, becomes negative again and is impor
tant for highly polar molecules.