Group additive modeling of cyclopentane pyrolysis

The pyrolysis of cyclopentane is not well established although it is an abundant compound in typical naphtha feedstocks and can be considered a model compound for cyclic fuels. The studies in literature so far have focused primarily on the initial decomposition of cyclopentane in shock tubes. This article therefore explores the pyrolysis of cyclopentane in a continuous flow tubular reactor with pure cyclopentane feed at reactor conditions 0.17 MPa, 973-1073 K, and a residence time of 0.5s. Conversions of 5% to 75% were realized while the product concentrations were quantified using two dimensional gas chromatography. A mechanism composed of elementary high pressure limit reactions has been generated using the automatic network generation tool “Genesys”. Kinetics of the reactions originate from high level ab-initio calculations and new group additive values derived from ab-initio kinetic data in literature. Overall the Genesys model outperforms the models available in literature and there is a good agreement between model calculated mass fraction profiles and experimental data for 22 products ranging from hydrogen to naphthalene without any adjustments of the kinetic parameters. Reaction path analysis reveals that cyclopentane consumption is initiated by the unimolecular isomerization to 1-pentene, but overall dominated by hydrogen abstraction reactions by allyl radicals and hydrogen atoms to give cyclopentyl radicals, whose ring opening and further scissions lead to smaller molecules. Dominant routes for the major products are discussed.