Test of the validity of some kerogen models based on oxidative degradation

Abstract

Molecular models of considerable complexity have been proposed recently for type I, II and III kerogens. Here, we describe the amount and type of carboxylic acids that one would expect to result from their multistep alkaline permanganate oxidation, based on literature data for the oxidation of a range of kerogens. This exercise was aimed at providing useful data for the possible improvement of the proposed models. Discrepancies arise between the products of the oxidation of isolated kerogens, as obtained in practice, and those expected from the oxidation of the three model kerogens. These are, principally, that the models do not allow for the appearance of aliphatic monocarboxylic, isoprenoid and alkyl-substituted aromatic acids, there are discrepant distributions, or proportions, of α,ω-dicarboxylic, aromatic and phenolic, and alkane-carboxylic or cycloalkanoic acids in the model oxidation products. The presence of more easily and completely degradable structural units in the kerogen models are also anomalous.