Hydrocarbons vapor density ratio

The van t Hoff equation also has been used to describe the temperature effect on Henry s law constant over a narrow range for volatile chlorinated organic chemicals (Ashworth et al. 1988) and chlorobenzenes, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons (ten Hulscher et al. 1992, Alaee et al. 1996). Henry s law constant can be expressed as the ratio of vapor pressure to solubility, i.e., pic or plx for dilute solutions. Note that since H is expressed using a volumetric concentration, it is also affected by the effect of temperature on liquid density whereas kH using mole fraction is unaffected by liquid density (Tucker and Christian 1979), thus... 

A number of factors contribute to the effectiveness of foam as a vapor-suppressant. These include the type of foam, its expansion ratio, its drainage time, the rate of application of the foam (gal per min/ft2), and its application density (gal/ft2). Chemical foams have become obsolete, with mechanical foams now being used worldwide. A mechanical foam that has recognized attributes for vapor suppression is aqueous film-forming foam (AFFF). It is a synthetic foam (as compared to protein foams) with a surfactant that is part fluorochemical and part hydrocarbon. It suppresses vapors by forming an aqueous film produced by draining its foam bubbles. 

Further study about hydrocarbons/water separation was made by Yang et while using 4,4-bis(chloromethyl)biphenyl incorporated with triphenylamine. By changing the monomer ratio, a series of hypercrosslinked polymers were obtained with high surface areas and a predominantly microporous structure. With apparent BET surface areas of 1362 m g for PBP-N-25 and 1338 m g for PBP-N-50, the benzene/water vapor selectivity was as high as 53.5 and 63.6, respectively. Moreover, a monolithic polymer (M-PBP-N-25) was prepared with an apparent BET surface area of 551 m g. Owing to its hydrophobic nature and low density, the monolith showed the potential for applications in oil spill cleanup operations. 

---