Coal sample from salt range-pakistan has been analyzed to investigate its rank, hydrocarbon composition and most likely source of hydrocarbons. The rank of coal has been determined by general and chemical parameters. High percentage of volatile matter and sulfur content, low thermal characteristics and carbon and hydrogen content 62 and 5 respectively reveal that salt range coal is lignite in rank. In orser to determine hydrocarbon composition, bitumen was extracted from the coal and was fractionated into saturated, aromatic and NSO (nitrogen, sulfur and oxygen containing carbon) fractions by liquid chromatography employing silica gel. Further fractionation of aromatic fraction by TLC yielded two sub fraction called aromatic fraction #1 and aromatic fraction #2 respectively. Analysis of these fractions by capillary GC-FID showed a profile with high abundance of peaks that werecharacterized as thiophenic compounds. The identifications were based on the comparison of GC retention data with the literature. Dibenzothiophenes are the most abundant compounds in the Salt Range coal. Their methyl- and dimethyl substituted derivatives are also present in high concentration. Naphthalene and phenanthrene are present in minor amount but their alkyl substituted derivatives have relatively high concentration. The most likely source of aromatic hydrocarbons could be terpenoid precursors; however polynuclear aromatic thiophenes, could be formed from sulfur containing aromatic moieties of macromolecules during later stage of digenesis of the sediments. The incorporation of hydrogen sulfide into the precursor molecules could not be ruled out which is abundant in reducing environment.
T FAZEELAT ,M ASIF ,
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