Aromatic components of coal: relation of distribution pattern to rank

Aromatic distribution patterns have been evaluated for a series of twenty-four German high volatile bituminous B to low volatile bituminous coals of Upper Carboniferous Westphalian C-, B- and A-ages using high performance liquid chromatography and glass capillary gas chromatography. The study concentrates on dicyclic and tricyclic aromatic hydrocarbons most of which have been identified by combined gas chromatography-mass spectrometry. The distribution patterns of the methylhomologs of naphthalene and phenanthrene are strongly controlled by rank. A sudden increase of individual isomer ratios at 0.9% Rm coincides with an abrupt shift of the sporinite fluorescence colour from yellow towards red. A recently developed aromatics-derived maturity parameter, the Methylphenanthrene Index (MPI), correlated well with the vitrinite reflectance data over the whole rank range. Deviations have been attributed to variations of maceral composition or migration phenomena. The influence of artificial thermal alteration (350 and 400dgC) on the aromatic distribution pattern of coal is described.     

Novel 23,28-bisnorlupanes in Tertiary sediments. Widespread occurrence of nuclear demethylated triterpanes

A pair of isomeric C₂₈-bisnorlupanes was detected in high abundance in the saturated hydrocarbon fractions of Tertiary sediments from West Greenland and the Gulf of Suez. The compounds were isolated by preparative gas chromatography and the isomers separated by liquid chromatography. On the basis of mass spectrometric and nuclear magnetic resonance data the structures were assigned to be 17α(H)- and 17ß(H)-23,28-bisnorlupane, respectively. The significance of nuclear demethylated triterpanes is discussed in terms of their generally high abundance, their uneven distribution within a given facies, and their worldwide occurrence.