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8416964 
Meetings & Symposia 
Phase and vapor pressure behavior of binary systems of polycyclic aromatic compounds 
Fu, J; Rice, JW; Suuberg, EM 
2011 
0 
Abstracts of Papers of the American Chemical Society
ISSN: 0065-7727 
Anaheim, CA 
241st ACS National Meeting and Exposition 
English 
The majority of polycyclic aromatic compound (PAC) pollutants in the environment consist of mixtures of PACs, rather than being pure PACs. The present work concerns the phase and vapor pressure behaviors of binary PAC systems, as are determined by differential scanning calorimetry and the Knudsen effusion method, respectively. The system of pyrene + 9, 10-dibromoanthracene shows multiple phase characteristics and the existence of two preferred states, while the system of anthracene + 2-bromoanthracene forms a mixture with a maximum energy state at a particular composition. The solid-vapor equilibrium studies show that the vapor pressure of these systems depends on composition, but does not follow ideal Raoult's law behavior. Additionally, the vapor pressure studies also suggest the preferential formation of clusters of several molecules, and that the sublimation of these mixtures involves loss of these clusters from a surface. Similar sublimation behaviors are also found in other binary PAC systems. In addition, quantum chemical methods are developed to calculate the interaction energies between these PACs.