Changes in the composition of bitumen extracts and chemical structure of kerogen during hydrous pyrolysis

The paper presents data on the composition of biomarkers from bitumen extracts and the chemical structure of kerogen from C_org-rich sedimentary rocks before and after hydrothermal treatment in an autoclave at 300°C. Samples selected for this study are kukersite and Ordovician Dictyonema shale from the Baltics, Domanik oil shale from the Ukhta region, Upper Permian brown coal from the Pre-Ural foredeep, carbonaceous shale from the Oxfordian horizon of the Russian plate, and Upper Jurassic oil shales from the Sysola oil shale bearing region. The rocks contain type I, II, III, and II-S kerogens. The highest yield of extractable bitumen is achieved for Type II-S kerogen, whereas Type III kerogen produces the lowest amount of bitumen. The stages of organic matter thermal maturation achieved during the experiments correspond to a transition from PC_2–3 to MC_1–2. The ¹³C NMR data on kerogen indicate that the aromatic structures of geopolymers underwent significant changes.     

Analysis and characterization of ash-free coals from the Pechora coal basin obtained by organic solvent extraction

Doklady Earth Sciences - The probability of obtaining of ash-free coal extracts, so-called “hyper-coals,” has been shown for coals of the Pechora basin for the first time. The ash...     

Chemical structure and 13C NMR spectra of the kerogen of carbonaceous rock masses

The spectra of the kerogen from the Middle Volga oil shales of the Volga-Pechora shale province and from the Ukhta domanik’s carbonaceous deposits have been studied. In the Middle Volga and domanik kerogens, carbon-oxygen bonding types have been revealed as dominant. Significant distinctions between the two kerogen types have been established. The presence of oxygen in carbonyl and phenol groups is typical for the domanik kerogen, and also in ether bonds for the kerogen of the Middle Volga shale rock mass, which are of considerable importance in its structure.