Using elementary Reactions to Model Growth Processes of Polyaromatic Hydrocarbons under Pyrolysis Conditions of Light Feedstocks

Karen Hemelsoet (1) , Veronique van Speybroeck (2) , Kevin M. van Geem (3) , Guy B Marin (3) , Michel Waroquier (4)

1 Center for Molecular Modeling
2 Center for molecular modeling
3 Laboratory for Chemical Technology
4 Center for Molecular Modeling

Density Functional Theory results are presented for elementary steps leading to coke growth within a steam cracking unit. The discussed pathway starts from toluene and ultimately, 1-methylnaphthalene is formed. In order to find the rate determining step for coke formation, the pseudo first-order rate coefficients of the various steps are compared taking into account the concentrations of diverse coke precursors. The influence of the polyaromatic environment is studied for a large set of methylated polycyclic aromatic molecules, by means of carbon-hydrogen bond dissociation enthalpy values. Subsequent hydrogen abstraction reactions at the methylated polyaromatics, by a methyl radical, are also examined. The abstraction is found to preferentially occur at the larger systems and is in general faster compared to abstractions at the analogous non-methylated species.

Mots clés: Physical Sciences

Karen Hemelsoet, Veronique van Speybroeck, Kevin M. van Geem, Guy B Marin, Michel Waroquier. Using elementary Reactions to Model Growth Processes of Polyaromatic Hydrocarbons under Pyrolysis Conditions of Light Feedstocks. Molecular Simulation, 2008, 34 (02), pp.193-199. ⟨10.1080/08927020801930588⟩. ⟨hal-00515027⟩