Back to Search
Start Over
Computational study of polycyclic aromatic hydrocarbons growth by vinylacetylene addition.
- Source :
-
Combustion & Flame . Apr2019, Vol. 202, p276-291. 16p. - Publication Year :
- 2019
-
Abstract
- Abstract The growth of polycyclic aromatic hydrocarbons (PAH) can proceed via multiple chemical mechanisms. The mechanism of naphthyl radical and vinylacetylene (C 4 H 4) addition reaction has been systematically investigated in this computational study. A combination of DFT/B3LYP/6-311+G(d,p), CCSD/6-311+G(d,p) and CBS-QB3 methods were performed to calculate the potential energy surfaces. It revealed that the products, including phenanthrene, anthracene, a PAH with a five-membered ring structure, and PAH with a C 4 H 3 radical substitution, can be formed in A 2 -1 (1-naphthyl)+C 4 H 4 and A 2 -2 (2-naphthyl) +C 4 H 4 reaction networks. The reaction rate constants at 0.1-100 atm were evaluated by RRKM theory by solving the master equation in the temperature range of 800–2500 K, which showed that the rate constants of reactions A 2 -1 (A 2 -2)+C 4 H 4 →product+H are highly temperature-dependent but nearly pressure-independent. The distribution of products was investigated in a 0-D batch reactor, wherein the initial reactant concentrations were taken from experimental measurements. The results showed that adduct intermediates were the main products at low temperature (T < 1000 K), and the phenanthrene and PAH with C 4 H 3 radical substitution became the dominant products at temperatures where PAHs and soot form in flames (T > 1000 K). It was observed that a significant amount of phenanthrene is formed from PAH with a C 4 H 3 radical substitution with the assistance of H atom. Reaction pathway sensitivity analysis for the PAH radical+C 4 H 4 reaction system was performed and showed that the new benzene rings are more likely to be generated near the zig-zag edge surface site instead of the free edge. For the development of a PAH mechanism, the analogous treatment of rate constants for larger PAH radical + C 4 H 4 reaction system are discussed. The formation rate of naphthalene from the reaction of phenyl+C 4 H 4 was found to be very close to that of phenanthrene from the reaction of naphthyl+C 4 H 4 , suggesting that the analogous treatment of the rates is reasonable in PAH mechanisms. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00102180
- Volume :
- 202
- Database :
- Academic Search Index
- Journal :
- Combustion & Flame
- Publication Type :
- Academic Journal
- Accession number :
- 134958255
- Full Text :
- https://doi.org/10.1016/j.combustflame.2019.01.023