Le Bas molar volumes

Accordingly, plots are presented at the end of each chapter for solubility, vapor pressure, Kow, and Henry s law constant versus Le Bas molar volume. 

As described earlier, Henry s law constants can be calculated from the ratio of vapor pressure and aqueous solubility. Henry s law constants do not show a simple linear pattern as solubility, Kqw or vapor pressure when plotted against simple molecular descriptors, such as numbers of chlorine or Le Bas molar volume, e.g., PCBs (Burkhard et al. 1985b), pesticides (Suntio et al. 1988), and chlorinated dioxins (Shiu et al. 1988). Henry s law constants can be estimated from ... 

The molar volumes are in some cases at the stated temperature and in other cases at the normal boiling point. Certain calculated molecular volumes are also used thus the reader is cautioned to ensure that when using a molar volume in any correlation, it is correctly selected. In the case of polynuclear aromatic hydrocarbons, the Le Bas molar volume is regarded as suspect because of the compact nature of the multi-ring compounds. It should thus be regarded as merely an indication of relative volume, not an absolute volume. 

Figures 1.7.1 to 1.7.4 show the dependence of the physical-chemical properties on Le Bas molar volume. Figure 1.7.1 shows that the solubilities of the monoaromatics decrease steadily with increasing molar volume. The vapor pressure data in Figure 1.7.2 are similar, but log KoW in Figure 1.7.3 increases with increasing molar volume also in a linear fashion.

FIGURE 1.7.1 Molar solubility (liquid or supercooled liquid) versus Le Bas molar volume for mononuclear aromatic hydrocarbons. 

FIGURE 1.7.12 Octanol-water partition coefficient versus Le Bas molar volume for alky I phenols and chlorophenols. 

FIGURE 2.2.8 Henry s I aw constant versus Le Bas molar volume for aliphatic and cyclic hydrocarbons. 

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