Characterization of victorian soft brown coal wood by microscopic techniques and Curie-Point pyrolysis combined with gas chromatography-mass spectrometry

Pyrolysis combined with gas chromatography-mass spectrometry is used in an attempt to distinguish lignins derived from an angiosperm and a gymnosperm on the basis of their pyrolysis products. The study is extended to examine the pyrolysis products of Australian soft brown coal woods that have undergone varying degrees of gelification during the soft brown coal stage of coalification. Comparison of the lignin and brown coal pyrograms shows that the brown coals may be derived from gymnosperms, which is in agreement with the results of previous microscopic studies. Poorly gelified brown coals are also shown to contain significant amounts of furan-type products which are not present in the gelified soft brown coal woods. No systematic variation was observed in the distribution of methoxy compounds and the macroscopically and microscopically defined degree of gelification. Finally pyrolysis of low rank vitrinites shows a relative lack of substituted phenols in their pyrograms, but a relative increase in concentration of substituted polycyclic aromatics, compared with highly gelified brown coals.