Oxidation of oil shale kerogen by alkaline potassium permanganate

We carried out the analytical oxidation of kerogen samples from oil shales of Ordovician kukersite from the Baltic region, Domanik shales from Timan-Pechora and Upper Jurassic oil shales of the Kashpir deposit by potassium permanganate in an alkaline medium. We performed a single-stage oxidation with 3.5 % solution of potassium permanganate, followed by analysis of trimethylsilyl derivatives of carboxylic acids using chromatography-mass spectrometry, and multi-stage oxidation by 0.5 % solution of potassium permanganate and analysis of oxidation products using IR spectroscopy. Some n-alkyl structures are peripherally associated with the kerogen matrix in the kerogen of Domanik and Jurassic shales, while in the structure of kukersite kerogen, n-alkyl structures are mainly connecting links for larger fragments. Milder, in case of a multi-stage process, oxidation results in formation of large fragments of kerogen, generally repeating its carbon structure, but more oxidized.