Investigation on the Thermal Decomposition of Cyclic Hydrocarbons with the Shock Tube Technique

The reactions involving aromatic hydrocarbons play a crucial role in the combustion chemistry for the formation and growth of polyaromatic hydrocarbons (PAHs). In this work, the thermal decomposition of the single ring aromatics benzene, phenyl and ortho-benzyne have been investigated behind reflected shock waves by using a sensitive detection technique - Atomic Resonance Absorption Spectroscopy (ARAS).

The unimolecular decomposition of ortho-benzyne was investigated behind reflected shock waves by taking 1,2-diiodobenzene as the thermal source. The initial concentration of ortho-benzyne was determined in situ with I-ARAS. Simultaneously, the progress of reaction was monitored by measuring the produced H atoms with H-ARAS. By reproducing the experimental H atom concentration time profiles, a two channel decomposition model of ortho-benzyne was developed.

By investigating the thermal decomposition of phenyl and benzene, a complete detailed chemical reaction model was elaborated which is able to capture the measured H atom concentration profiles over the whole investigated parameter range.

Thus, the present work may contribute to a better understanding and describing of high temperature combustion of aromates which are considered as major soot precursors.