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Hydrogen transfer reaction in polycyclic aromatic hydrocarbon radicals
Huiting Liu1, Liuming Yan, Baohua Yue
1Department of Chemistry, Innovative Drug Research Center, College of Sciences ‡ Research Center for Composite Materials Shanghai University , 99 Shangda Road, Shanghai 200444, China.
The Journal of Physical Chemistry. A
|June 4, 2014
Summary
This study reveals that hydrogen transfer in chemical vapor infiltration is nearly spontaneous between bay sites, with low energy barriers. Armchair sites show lower barriers than zigzag sites for these crucial reactions.
Area of Science:
- Computational chemistry
- Materials science
Background:
- Chemical vapor infiltration (CVI) is vital for advanced material fabrication.
- Understanding hydrocarbon radical formation and hydrogen transfer is key to optimizing CVI processes.
Purpose of the Study:
- To investigate hydrocarbon radical formation and hydrogen transfer pathways in CVI using model polycyclic aromatic hydrocarbons (PAHs).
- To calculate hydrogen transfer reaction rate constants and identify key reaction sites.
Main Methods:
- Density Functional Theory (DFT) calculations were employed to model molecular interactions.
- Rice-Ramsperger-Kassel-Marcus (RRKM) theory and Transition State Theory (TST) were used to determine reaction rate constants.
Main Results:
- Hydrogen transfer between bay sites is nearly spontaneous, with a low energy barrier of approximately 4.0 kcal mol(-1).
- Hydrogen transfer reactions exhibit lower energy barriers between armchair sites compared to zigzag sites.
Conclusions:
- The study elucidates critical hydrogen transfer mechanisms in CVI relevant to PAH precursors.
- DFT and kinetic theories provide valuable insights into reaction energetics and pathways, guiding CVI process optimization.
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