Pyrolysis and spectroscopy of cyclic aromatic combustion intermediates.

摘要

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), 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 tabletop 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 and 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.