An experimental, theoretical and modeling study of the pyrolysis and oxidation of propan-1-ol using CO time-history measurements behind reflected shock waves

The pyrolysis and oxidation of propan-1-ol were investigated in this work, providing new experimental data that highlight the limitations of the most recent detailed kinetic mechanisms available in the literature. The new data, obtained near atmospheric pressure, consist of shock-tube CO time-history profiles measured behind reflected shock waves using laser absorption diagnostics near 4.6 μm. Pyrolysis experiments were conducted with mixtures of propan-1-ol highly diluted in He/Ar (20/79.75%) within a temperature range of 1217 to 1592 K. Oxidation was studied at three different equivalence ratios, φ = 0.5, 1, and 2, using highly diluted mixtures of propan-1-ol/O 2 / He/Ar (20/79.5% He/Ar) over a temperature range of 1284 to 1696 K. Under these high-temperature conditions, accounting for the pressure dependency of the rate constants of unimolecular initiation reactions (including dehydration) is of paramount importance. Channel-specific rate constants were therefore theoretically determined using variable reaction coordinate transition state theory in the temperature and pressure ranges of interest for propan-1-ol pyrolysis and combustion. These theoretical results, together with a recent work on H-abstraction reactions by H and OH, and the reactions of the successive C 3 H 7 O radicals, were incorporated into a detailed kinetic mechanism able to predict CO formation. This mechanism was also successfully tested against experimental data obtained under various conditions in the literature. Rate-of-production analyses were performed and showed that CO formation is positively sensitive to the decomposition of propan-1-ol into ethyl and hydroxymethyl radicals during the early stages of the reaction, while the formation of the β-radical by H-abstraction inhibits CO formation.