SULFUR CONTAINING HETERO AROMATICS

Arabian Light crude is a wider boiling material than crude shale oil and is lower in all hetero atoms except sulfur. It has a more favorable carbon/hydrogen ratio because it contains fewer aromatics and no olefins. 

Recently, the application of short term bio-assays to a variety of emission and ambient particulate samples has demonstrated that other compounds than PAH, most likely PAH-derivatives, can be responsable for a major part of the observed biological activity of the extracts. These results have forced us to widen our interest to the field of particulate polycyclic organic matter (POM), which besides hetero-atomic PAH (polycyclic aromatic compounds, PAC, containing nitrogen or sulfur) may also contain oxidized, nitrated, or sulfonated derivatives of PAH, formed in exhausts, emission stacks, plumes or during transport through the atmosphere. 

Furan 84 is a five-membered r-excessive aromatic heterocycle containing one hetero oxygen atom. It is unstable in acids, forming tars, so like pyrrole (Chapter 6, p 182) the substrate cannot be sulfonated by sulfuric or chlorosulfonic acid. However, again like pyrrole, treatment of furan 84 with sulfur trioxide in either dioxan or pyridine yields the 2-sulfonic acid 85 (Equation 23). 

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