Molecular characterization of kerogens by mild selective chemical degradation — ruthenium tetroxide oxidation

Abstract

Molecular characterization of two kerogen isolates (Messel and Kimmeridge Clay), two kerogen-rich shales (Green River and Maoming) and a coal, (Loy Yang) was undertaken using selective chemical degradation with ruthenium tetroxide (RuO 4). The RuO 4 oxidation gave extracts which were soluble in dichloromethane and contained series of straight chain monocarboxylic acids, α,ω-dicarboxylic acids, branched mono- and dicarboxylic acids, isoprenoid and cyclic acids. Straight chain carboxylic acids were predominant (65–87% of quantified chromatogram components for the range of sedimentary organic matter studied), reflecting the major content of polymethylene chains in these kerogens. This mild, oxidative technique serves to differentiate kerogens at a molecular level, thereby supplementing existing conventional chemical, pyrolytic, n.m.r. and other techniques.