Diphenyl, physical constants

In the case of the war gases, this physical constant has an especial interest. In order to be of use in warfare, at least as a toxic agent on the respiratory tract, a gas must have a vapour pressure high enough at ordinary temperatures to supply enough gas to the atmosphere to produce useful physiopathological effects. However, this property has only a minor value in the case of substances such as diphenyl dichloroarsine, which are used in the form of aerosols. 

Purely aromatic ethers e.g., diphenyl ether), which are commonly encountered, are very hmited in number. Most of the aromatic ethers are of the mixed aliphatic - aromatic type. They are not attacked by sodium nor by dilute acids or alkahs. When hquid, the physical proper-ties (b.p., d . and ) are useful constants to assist in their identification. Three important procedures are available for the characterisation of aromatic ethers. 

Polybrominated Diphenyl Ethers. Many of the relevant physical and chemical properties of the PBDEs are not available (see Table 4-4). Very limited data are available on the physical and chemical properties for the individual congeners. Important data, such as vapor pressure, and Henry s law constant, are necessary for the prediction of the environmental fate and transport ofPBDEs. 

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