Abstract
Measurements are reported
of the slope of the critical locus of binary mixtures of a series of
hydrocarbons, and two fluorocarbons, with hydrogen near the critical point of
the hydrocarbon (or fluorocarbon).These systems exhibit
gas-gas immiscibility of the first kind. The results are compared with predictions
from the one-fluid model together with 'a hard sphere + attractive term'
equation of state proposed by Guggenheim.
The results can be predicted from the theory provided the energy
interaction parameter, ξ, is allowed to be somewhat less than that
calculated from the Hudson and McCoubrey rule. This
is discussed in terms of values of ξ from other measurements, and possible
deficiencies in the theory.