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The density functional theory (DFT) was used along with isodesmic reaction schemes to estimate heats of formation for aromatics and polynuclear aromatic hydrocarbons (PAHs). The methodology for creating and using appropriate ring conserved isodesmic reaction is discussed.

Research was conducted to examine the pyrolysis and oxidation of phenol. The objective of the study is to acquire experimental oxidation data over a range of stoichiometries as well as complementary phenol pyrolysis data. Results indicate that cyclopentadiene is a major reaction intermediate. Reaction intermediates are consistent not only with the findings of a cyclopentadiene oxidation study but also with reactions in the postulated mechanism of phenol oxidation.

The pyrolysis of toluene, the simplest methyl-substituted aromatic molecule is studied behind reflected shock waves using a single pulse shock tube to understand the modeling of benzyl decomposition. Viable pathways are tested for the growth of key soot precursors such as [C.sub.2][H.sub.2], [C.sub.4][H.sub.2], [C.sub.8][H.sub.6] and indene.

The pyrolysis of toluene is studied behind reflected shock waves, using a single pulse shock tube, by performing experiments at nominal high pressures of 27 and 45 bar and a wide temperature range of 1200 to 1900 K. The high pressure limiting rate constants obtained indicate high-temperature branching ratios for the primary steps that vary from 0.39 to 0.52 over the temperature range 1200-1800 K.

The implementation of techniques aimed at improving engine performance and reducing particulate matter (PM) pollutant emissions is strongly influenced by the limited understanding of the polycyclic aromatic hydrocarbons (PAH) formation chemistry, in combustion devices, that produces the PM emissions. New experimental results which examine the formation of multi-ring compounds are required. The present investigation focuses on two techniques for such an experimental examination by recovery of PAH compounds from a typical combustion oriented experimental apparatus. The online technique discussed constitutes an optimal solution but not always feasible approach. Nevertheless, a detailed description of a new online sampling system is provided which can serve as reference for future applications to different experimental set-ups. In comparison, an offline technique, which is sometimes more experimentally feasible but not necessarily optimal, has been studied in detail for the recovery of a variety of compounds with different properties, including naphthalene, biphenyl, and iodobenzene. The recovery results from both techniques were excellent with an error in the total carbon balance of around 10% for the online technique and an uncertainty in the measurement of the single species of around 7% for the offline technique. Although both techniques proved to be suitable for measurement of large PAH compounds, the online technique represents the optimal solution in view of the simplicity of the corresponding experimental procedure. On the other hand, the offline technique represents a valuable solution in those cases where the online technique cannot be implemented. [ABSTRACT FROM AUTHOR]