The asphaltene fraction from a super-critical gas (SCG) extract of bituminous coal was pyrolysed under nitrogen at temperatures from 200 to 450 °C, and the resultant pyrolysate re-fractionated into four conventional solubility classes (n-pentane-soluble, benzene-soluble, pyridine-soluble and pyridine-insoluble). The present work describes the characterization of the n-pentane-soluble fraction by combined gas chromatography-mass spectrometry. Preliminary studies indicated that asphaltenes, conventionally isolated, occlude significant amounts of pentane-soluble material and a multiple precipitation procedure for generating a 'clean' asphaltene was accordingly adopted. A very complex mix of pentane-soluble material was generated from the asphaltenes at the ˜2-4% level throughout the entire pyrolysis temperature range. The products identified included (1) n-alkanes (2) alkylbenzenes (3) alkylnaphthalenes (4) indanes (5) biphenyls (6) phenols and (7) other minor constituents such as fluorene and phenanthrenes. They were separated by capillary g.c. and identified either by co-injection of standards or from their mass spectral properties using comparison with a computer accessed library of mass spectral data. The major products of pyrolysis of SCG asphaltenes are benzene-insoluble fractions (including pyridine-insolubles); the formation of these is associated with the reduction of phenolic content of the asphaltene pyrolysand. © 1983.
|Number of pages||5|
|Publication status||Published - Jun 1983|
- coal liquefaction