Aromatic aldehydes and ketones in the Posidonia shale, Hils syncline, Germany

The low-polarity NSO compound fraction of Posidonia Shale bitumens has prev iously been shown to contain fluoren-9-ones and benzofluoren-9-ones as the quantitatively most abundant compound class. The present study, based on de tailed gas chromatography-mass spectrometry describes the distribution of n aphthaldehydes, alkylnaphthylketones: benzaldehydes, alkylphenylketones. 1- indanones and 1-tetralones as additional types of aromatic carbonyl compoun ds in these samples. Benzene-derived carbonyl compounds are less abundant t han the other identified compound classes. The observed distributions show some remarkable maturity related variations. Particularly, the ratios of al pha- and beta-isomers of naphthalene-derived carbonyl compounds behave in a similar manner to the corresponding hydrocarbons, i.e. they show a relativ e increase of the p-isomers with increasing maturity. The 1-indanone/(1-ind anone + 1-tetralone) ratio (ITR) is suggested as a new heterocompound based maturity parameter. The carbonyl compounds described map be derived either from inter- and/or intramolecular acylation and formylation reactions or f rom oxidation of benzylic methylene groups of alkylated aromatic hydrocarbo ns. (C) 1998 Elsevier Science Ltd. All rights reserved.