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Pyrolysis and Spectroscopy of Cyclic Aromatic Combustion Intermediates

TitlePyrolysis and Spectroscopy of Cyclic Aromatic Combustion Intermediates
Publication TypeThesis
Year of Publication2016
AuthorsBuckingham, GT
Academic DepartmentDepartment of Chemistry and Biochemistry
DegreePh.D.
Number of Pages346
Date Published04-2016
UniversityUniversity of Colorado
CityBoulder, CO
Abstract

We have studied the pyrolysis of aromatic combustion intermediates using an array of detection techniques. The molecules investigated include cyclic aromatic molecules with hydrocarbon substituents (ethylbenzene, n-propylbenzene, isopropylbenzene, and styrene), oxygen-containing substituents (anisole and phenol), triply substituted systems (vanillin), resonance stabilized radicals (benzyl radical and tropyl radical) and phenyl radical. At the exit of a resistively heated micro-reactor (1 mm inner diameter, 3 cm long), the pyrolysis fragments are detected using photoionization mass spectrometry (PIMS), matrix isolation vibrational spectroscopy, microwave spectroscopy, tunable VUV synchrotron-based PIMS, and table-top VUV PIMS with photoelectron photoion coincidence spectroscopy (PEPICO). This array of detection methods allows for the identification of all possible fragments including metastables, radicals, and atoms. The findings allow for detailed mechanistic information regarding which pathways are active at different pyrolysis temperatures. The findings can also be used to help identify products and individual isomers that are formed during the gas-phase thermal decomposition of aromatic systems. By providing direct experimental pyrolysis data, models for fuel decomposition and soot formation can be improved to help understand current combustion systems and eventually aid in the design of superior fuel sources in the near future.