Asphaltene Reaction Pathways. 2. Pyrolysis of n-Pentadecylbenzene

The reactions, pathways, kinetics, and mechanisms of alkyl-aromatic moieties likely present in asphaltenes were probed via the thermolysis of n-pentadecylbenzene (PDB) at temperatures from 375 to 450 °C. The primary reaction pathway led to two major product pairs, toluene plus 1-tetradecene and styrene plus n-tridecane, respectively. A complete series of n-alkanes, a-olefins, phenylalkanes, and phenylolefins was also formed in lesser yields. PDB thermolysis was demonstrably first-order, and associated Arrhenius parameters of [E* (kcal/mol), log A (s^-1)] = [55.45,14.04] were determined. Reaction in tetralin-d₁₂indicated that the operative PDB thermolysis mechanism was entirely free-radical. This information permitted speculation into the relevance of the model-compound results to asphaltene reactions.