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Download fileH‑Atom-Forming Reaction Pathways in the Pyrolysis of Furan, 2‑Methylfuran, and 2,5-Dimethylfuran: A Shock-Tube and Modeling Study
journal contribution
posted on 2018-07-23, 00:00 authored by Isabelle Weber, Philipp Friese, Matthias OlzmannThe
methyl-substituted furan derivatives 2-methylfuran (2-MF) and
2,5-dimethylfuran (2,5-DMF) are often discussed as alternative fuels.
Despite the large number of mechanistic studies on the pyrolysis and
oxidation of 2-MF, 2,5-DMF, and unsubstituted furan (F), detailed
kinetic investigations of the initial reaction steps are scarce. In
this work, we report on shock-tube studies with detection of hydrogen
atoms by atom resonance absorption spectroscopy to investigate the
thermal decomposition of F, 2-MF, and 2,5-DMF. Hydrogen atom concentration–time
profiles were recorded behind reflected shock waves at temperatures
between 1200 and 1900 K and pressures between 0.7 and 1.6 bar with
Ar as the bath gas. The recorded profiles were compared with results
from kinetic simulations performed on the basis of a joint F/2-MF/2,5-DMF
oxidation mechanism recently published. Kinetic parameters for a small
number of reactions with high sensitivities for the formation and
consumption of H atoms were adapted by taking values from other references
to improve the agreement of the experimentally determined and simulated
concentration–time profiles. In this way, an adequate description
of the H atom concentration–time profiles for all three furan
derivatives with the joint mechanism could be achieved. On the basis
of this adapted mechanism, the formation pathways of H atoms in the
pyrolysis of all three furan derivatives were identified and analyzed.
It turned out that the formation of H atoms in the case of 2-MF and
2,5-DMF is governed by a competition between H split-off from the
methyl group(s) of the reactant molecule as well as from the primary
ring-opening product. In the case of F, only decomposition steps of
the ring-opening product are relevant. The adapted mechanism is given
in machine-readable form for modeling purposes, and the alterations
made are discussed.