Pyrolysis of SCG extract coal asphaltenes: Gas chromatographic-mass spectroscopic study of the n-pentane soluble fraction
✍ Scribed by S.J.W. Grigson; W. Kemp; P.R. Ludgate; W. Steedman
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 547 KB
- Volume
- 62
- Category
- Article
- ISSN
- 0016-2361
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✦ Synopsis
The asphaltene fraction from a super-critical gas (SCG) extract of bituminous coal was pyrolysed under nitrogen at temperatures from 200 to 45o"C, and the resultant pyrolysate re-fractionated into four conventional solubility classes (n-pentane-soluble, benzene-soluble, pyridine-soluble and pyridineinsoluble). 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 ~24% 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 gc. 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.