The origin of alkylbenzenes and thiophenes in pyrolysates of geochemical samples

Alkylbenzenes and thiophenes are common in pyrolysates of sulphur-rich oils, kerogens, coals and humic substances. The formation of alkylbenzenes and alkylthiophenes as artifacts during flash pyrolysis of triglycerides, or unsaturated fatty acids, in the presence of elemental sulphur is proved, which suggests that these alkylated cyclic and heterocyclic compounds may have at least two origins: as evaporation/pyrolysis products from the macromolecular matrix, and/or as artifacts. Therefore, inferences made from the presence of such homologous series of compounds in pyrolysates should be drawn with caution.