Experimental and kinetic modeling study on 1,3-cyclopentadiene oxidation and pyrolysis

The oxidation of 1,3-cyclopentadiene (c-C5H6), a key intermediate formed in the combustion of aromatic and cyclic hydrocarbon fuels and formation of polycyclic aromatic hydrocarbons (PAHs), was studied in a jet-stirred reactor (JSR) under the pressure of 0.1 MPa and temperatures from 623 to 1073 K with three equivalence ratios (φ = 0.5, 1.0 and 1.8). The mole fraction profiles of 25 oxidation products including light hydrocarbons, oxygenated and aromatic species were identified and quantified using online synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) with uncertainties of C, H, and O molar balances about 24%, 20% and 14%, respectively. A detailed kinetic model with 245 species and 1638 reactions was constructed based on the theoretical calculation and reported models in literature and validated with the new JSR oxidation data in this work. The dominant consumption channels of 1,3-cyclopentadiene are through H-atom abstraction reactions by OH, HO2 and CH3 radicals to produce cyclopentadienyl radical (c-C5H5) under all equivalence ratios and the contribution of CH3 attacking increases from φ = 0.5 to 1.8. Subsequently, the c-C5H5 is consumed via the reactions with HO2 and O2 to form small molecule and the recombination reaction with c-C5H6 to yield PAHs. Furthermore, the current model was also validated with a wide range of experimental data in literature of 1,3-cyclopentadiene combustion, including the species concentration profiles in flow reactors pyrolysis and oxidation.