Aromatic compounds, identification coals

The newly developed 600 MHz NMR Spectrometer is used to characterize coal-derived liquids and their chromatographically separated fractions. The distinct and well resolved proton resonance lines in both aromatic and aliphatic regions and IR analysis have been used to identify the major compounds and compound types. Double resonance technique has been applied for the chemical shift identification of donor protons (or-CHg, p-CH,) of partially hydrogenated polynuclear aromatic compounds. An NMR difference technique is applied to determine specific compositional changes in upgraded liquids derived under identical process conditions, but from different coal sources. 

Kennaway, E. (1955). Identification of carcinogenic compound in coal tar. Br Med J 2, 749—752. Kohan, M. J., Sangaiah, R., Ball, L. M., and Gold, A. (1985). Bacterial mutagenicity of aceanthrylene a novel cyclopenta-fused polycyclic aromatic hydrocarbon of low molecular weight. Mutat Res 155, 95-98. 

PASHs are present in fossilized matter such as coal, mineral oil, and derived products, and are released into ambient air by combustion processes. Their chemical stability causes them to be farther distributed to other environmental compartments. Many PASHs share the carcinogenic and mutagenic properties of PAHs, and are therefore a significant health issue. It is well known that subtle changes to the skeleton or alkylation pattern of aromatic compounds can drastically alter their carcinogenic potential, prompting demands for the improved identification and quantification of such compounds in the environment. 

Coincident with the development of sampling procedures were the constant iterative improvements in extraction, separation, identification and quantitation of organic compounds. Special emphasis was placed on selected compound classes such as the polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated benzenes, and chlorinated dibenzo-p-dioxins (dioxins). The best available procedures were used to determine these components because they have known acute or chronic effects and previous studies suggested that they might be present in effluents from the combustion of coal alone and combination coal/RDF. 

The chemical synonyms and identification numbers for wood creosote, coal tar creosote, and coal tar are listed in Tables 4-1 through 4-3. Coal tar pitch is similar in composition to coal tar creosote and is not presented separately. Coal tar pitch volatiles are compounds given off from coal tar pitch when it is heated. The volatile component is not shown separately because it varies with the composition of the pitch. Creosotes and coal tars are complex mixtures of variable composition containing primarily condensed aromatic ring compounds (coal-derived substances) or phenols (wood creosote). Therefore, it is not possible to represent these materials with a single chemical formula and structure. The sources, chemical properties, and composition of coal tar creosote, coal tar pitch, and coal tar justify treating these materials as a whole. Wood creosote is discussed separately because it is different in nature, use, and risk. 

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