Chlorobenzene, 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... 

Equilibrium partitioning was observed with trichlorobiphenyls and the chlorobenzenes, while the tetra- and pentachloro dioxins and furans, and heptachloro-biphenyls distributed into the vegetation by kinetically limited gaseous uptake. Octochloro dioxins and furans along with the higher molecular weight PAHs distributed onto plants by particle deposition. This would be consistent with the known propensity of the latter to distribute onto particles. These data also provide an opportunity to evaluate differences among plant species and the ratio of surface to volume accounted for much of the variation observed. 

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