Nitrobenzene, molecular volume

In all cases, both permeability and diffusivity of methyl-substituted benzenes vary in an inverse manner with their molecular volumes (as calculated by dividing the molecular weight by density and Avogadro number to yield the volume per molecule). For other penetrants, namely, anisole, nitrobenzene, chlorobenzene, -dichlorobenzene and bromobenzene, the volume per molecule varies in the range 17-19. However, their diffusion trends are quite different. For instance, though nitrobenzene and chlorobenzene... 

Equations 10.65a and 10.65b yield an excellent description of the mole fractions of the coexisting liquid phases as a function of temperature. As an example we show in Figure 10.3 Axcxc and Ax of four hydrocarbon solutions in nitrobenzene. Wang et al have found empirical evidence that the asymmetry coefficients aefr and efr are related to the ratio of the molecular volumes of the two components. 

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