The humic substances in Bayer liquor from a bauxite alumina refinery operating at 145−150 °C have been separated by dialysis into seven fractions of different molecular weight and characterized by acidity, nuclear magnetic resonance (NMR) spectroscopy, infrared spectroscopy, pyrolysis gas chromatography mass spectrometry (py-GC/MS), and thermogravimetric techniques including modulated differential scanning calorimetry. The higher molecular weight fractions contained more aromatic carbon than the lower molecular weight fractions (e.g., >300 000 Da, 56.4%; < 1200 Da, 33.6%). Acidity, NMR, and infrared spectroscopy indicate that carboxylic groups are more prevalent in lower molecular weight fractions (e.g., <1200 Da, 20.1%) than higher molecular weight fractions (e.g., >300 000 Da, 9.8%). Some fractions have particularly interesting structures and properties. For example, lignin-derived humic substances seem to concentrate in the 6000−12 000 Da fraction, as indicated by lignin guaiacyl residues. Involatile polycondensed material concentrates in the molecular weight fraction >300 000 Da. This fraction could be best described as soluble char with unusual properties such as the capacity to hold occluded water above 200 °C.

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Mixtures of barium (or strontium) salts and kerogen residues, after pyrolysis at 450 "C, produce endohedral metallofullerene ions on laser irradiation at low laser powers.

Infrared emission spectroscopy has been used to monitor the chemical modifications taking place in the organic and inorganic components during the pyrolysis of Kerosene Creek shale and the products of its demineralization. The samples were heated in the range 50-700 °C in the presence of argon. The results show the progressive decrease of the signals due to CH2 and CH3 vibrations, as well as the carbonyl and carboxylic peaks, and their subsequent disappearance at higher temperatures. Also evident is the appearance of a signal due to aromatic protons at ~450 °C for some samples. The effectiveness of the demineralization procedure can be assessed by comparing the spectra of the raw and demineralized shale. These results have been compared with room temperature transmission spectra of the same samples.

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