Reactivity of the aliphatic humic moiety in analytical pyrolysis

Humic acid from a podzol soil was subjected to conventional flash pyrolysis and pyrolysis/methylation in the presence or absence of elemental sulfur. In conventional pyrolysis, fatty and aliphatic dicarboxylic acids decarboxylate. In addition, cyclization and aromatization reactions of aliphatic chains lead to the formation of alkylbenzenes, indenes, naphthalenes, etc. These reactions are enhanced by sulfur and, in addition to the production of alkylaromatic compounds, aliphatic chains react with sulfur to form alkylthiophenes, dimethyl(poly)sulfides, etc. Pyrolysis/methylation largely prevents such reactions.