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An Australian bituminous coal has been heated, both alone and in the presence of bentonite, from 200 to 360°C over a period of 4 days. The heating sequence was designed to simulate coalification in a subsiding basin in which volatiles are confined to the generating sequence. The clay particles act as centres for catalytic cracking of volatile matter which cannot then adsorb within the coal on cooling. Evidence for deposition of “carbon” within the clay comes from thermal analysis, light microscopy and transmission electron microscopy. GC-MS data show that polycyclic aromatic hydrocarbons are only present in the free oil that is generated during maturation when clay is available as a catalyst.

Rundle oil shale containing 12.9 wt.% of organic carbon was retorted using a combustion-type retort. It was possible to quantify the reduction in oil yield (compared with Fischer assay) due to the combustion of oil vapour during retorting. The oil yield was only 7.2 wt.%, compared with a Fischer assay oil yield of 8.7 wt.%, when retorting was carried out with excess air but no additional source of carbon. Oil yields could be improved by mixing lignite, available from within the Rundle deposit, with oil shale before retorting. Oil yields, based on charge, from mixtures containing more than 10% lignite decreased with increasing lignite content, but were virtually identical with Fischer assay oil yields from the mixtures. The maximum oil yield was about 8.5 wt.% for 6 wt.% lignite in the mixtures. The resulting oils were slightly heavier and more aromatic than the oils obtained by Fischer assay, but showed no significant difference in oxygen content.

Oil shale and lignite from the Rundle/Stuart deposit and a range of mixtures of the two, have been pyrolysed in a Fischer retort. Oil yields decreased linearly from 8.67 to 5.19 wt% as the lignite content increased from 0 to 100%. Yields of gas, water and spent shale also varied linearly. H C atomic ratios of the resulting oils varied from 1.70 to 1.47 and, when plotted against oil shale percentage, a slightly concave curve resulted. Similarly, carbon aromaticity determined by n.m.r. varied from 0.33 to 0.48 and resulted in a slightly convex curve when graphed against oil shale content. It appears that oil produced by blending shale and lignite is more aromatic than expected for non-interacting components. Results show that oil from an intimate geological mixture is more aromatic than that from a comparable synthetic mixture.

The oxidation of carbon nanotubes and nanoparticles has been studied by thermogravimetric analysis (TGA) in air. The maximum rate of weight loss took place at 695[degrees]C at a heating rate of 1[degrees]C/min. This result shows that the nanotubes and nanoparticles are more resistant to oxidation than other forms of carbon diamond, soot, graphite, and C[sub 60] studied previously under identical conditions. The TGA of the nanotubes/nanoparticles in argon showed no weight change or detectable thermal transformation up to 1000[degrees]C. 18 refs., 1 fig.

The authors study the oxidation properties of purified C{sub 60}, in air. They find almost no weight gain due to the addition of oxygen, prior to the onset of weight loss. Rates of weigh loss are studied as a function of the heating rate for temperature rises varying from 1 to 20{degrees} per minute. The authors compare their results with other recent work, and offer explanations for the observed discrepancies.

Shale oil recovered from Fischer assays of fresh and artificially weathered oil shales have been compared using 1 H and 13 C nuclear magnetic resonance spectroscopy and elemental analyses. Rundle, Julia Creek and Green River shales were exposed to air at 100 °C for 60 weeks to simulate either geological weathering, or oxidation during drying or stockpiling prior to retorting. As a result of oxidation, the oils became more aromatic, with higher oxygen contents and shorter average aliphatic chain lengths. Variations in the distribution of phenols, acids and ketones, as well as heterocyclic compounds containing nitrogen and sulphur, have been detected.

Vanadyl porphyrins have been detected in a series of oil shale and weathered coquinite samples from the Toolebuc Formation, Queensland, Australia. Concentrations of soluble vanadyl porphyrins range from < 1 to 730 μg g−1. Organically bound vanadium has also been found in kerogens isolated from oil-shale samples taken at locations up to several hundred kilometres apart. Variations in the concentration of both vanadyl porphyrins and kerogen-bound V are probably due to recent weathering. By preferentially removing smaller aliphatic molecules, weathering progressively renders the remaining kerogen more aromatic and ultimately solubilizes all organic matter in the shales. At the same time, organically bound V is released and becomes associated with the inorganic fraction of the weathered shale.

A fresh sample of Rundle shale oil, recovered during retorting, was subjected to a variety of storage conditions for 26 weeks. Changes in chemical composition were investigated by Chromatographic and n.m.r. techniques. Subsamples of the fresh shale oil were stored at 1. (a) −4 °C under nitrogen 2. (b) 22 °C in air, in the dark 3. c) 22 °C in air, exposed to artificial light 4. (d) 10–35 °C in air, exposed to sunlight. The most significant changes were observed in the ‘sunlight’ sample. Exposure to sunlight caused a marked decrease in the aliphatic and mono-aromatic fractions in the aged shale oil with a corresponding increase in polar constituents. The ratio of straight-chain 1-alkenes to alkanes was significantly lower in this sample, while the ratio of 1-alkenes to internal alkenes was greatly increased. The reactivity of cis and trans -2-alkenes appeared to be similar during ageing experiments.