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Cleavage of an aromatic ring and radical migration
Alexander M Mebel1, Michael Frenklach2
1Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA. mebela@fiu.edu.
Faraday Discussions
|July 1, 2022
Summary
Thermal decomposition of aromatic-ring radicals was theoretically evaluated. Ring cleavage rates were found comparable to oxyradical decomposition in sooting flames, with surprisingly fast internal ring radical migration observed.
Area of Science:
- Combustion chemistry
- Theoretical chemical kinetics
- Polycyclic Aromatic Hydrocarbons (PAHs)
Background:
- Aromatic-ring radicals are key intermediates in combustion processes, influencing soot formation.
- Understanding their decomposition pathways is crucial for predicting combustion behavior and pollutant emissions.
Purpose of the Study:
- To theoretically investigate the thermal decomposition of various aromatic-ring radicals.
- To quantify reaction rates and explore decomposition mechanisms in simulated combustion environments.
Main Methods:
- Calculation of potential energy surfaces and reaction rate coefficients for naphthalenyl and pyrenyl radicals.
- Kinetic Monte-Carlo simulations of ethylene flames to model ring cleavage and migration.
Main Results:
- Thermal aromatic-ring cleavage rates were found to be significant, comparable to oxyradical decomposition in heavily sooting flames.
- Internal ring radical migration occurred at unexpectedly high frequencies, rivaling aromatic growth reactions.
Conclusions:
- Aromatic-ring radical decomposition plays a substantial role in combustion, particularly in sooting flames.
- The identified fast internal ring migration suggests novel reaction pathways influencing soot formation and growth mechanisms.
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