Reaction of cyclopentadienyl and methyl radicals

Vladislav S. Krasnoukhov (Login required)
Samara National Research University, Russia

Aleksander M. Mebel
Florida International University, Miami, FL, USA

Igor P. Zavershinskiy
Samara National Research University, Russia

Valeriy N. Azyazov
Samara National Research University, Russia
Lebedev Physical Institute, Samara, Russia

Paper #3131 received 04 Dec 2016; revised manuscript received 12 Mar 2017; accepted for publication 14 Mar 2017; published online 16 Mar 2017.

DOI: 10.18287/JBPE17.03.020304


Geometries and potential energies of reagents, products, and intermediate states for the reaction between cyclopentadienyl (C5H5) and methyl (CH3) radicals are found by means of ab initio quantum mechanical methods CCSD(T)/cc-pVTZ-f12, B2PLYPD3/AUG-CC-PVDZ and B3LYP/6-311G. Basing on the analysis of the found energy, structural and kinetic characteristics of the compounds involved, the reaction paths leading to the formation of fulvene and benzene, the simplest aromatic compound, are determined. The reaction path begins from the formation of the intermediate compound, methylcyclopentadiene, followed by tearing-off a hydrogen atom from it: C5H5 + CH3 → C5H5CH3 → C5H4CH3 + H. The subsequent monomolecular transformations of C5H4CH3 are closed by the formation of either fulvene (via the loss of one hydrogen atom from the methyl group) or benzene (via the stages of transforming the pentamerous ring into a hexamerous one and tearing-off a hydrogen atom). The rate constants found in the paper using the software package MESS show that the rate of benzene formation is always higher than that for fulvene within the temperature interval 500-2250 K. Since fulvene can also isomerize into benzene, the reaction C5H5 + CH3 is an important supplier of the initial bricks for building polycyclic aromatic hydrocarbons dangerous for living systems.


Combustion; methyl; cyclopentadienyl; benzene; fulvene; PANs; quantum chemistry calculations; reaction pathways; rate constant

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1. J. D. Bittner, and J. B. Howard, “Composition profiles and reaction mechanisms in a near-sooting premixed benzene/oxygen/argon flame,” Symposium (International) on Combustion 18(1), 1105-1116 (1981).

2. P. R. Westmoreland, A. M. Dean, J. B. Howard, and J. P. Longwell, “Experimental and theoretical analysis of oxidation and growth chemistry in a fuel-rich acetylene flame,” J. Phys. Chem. 93, 8171-8180 (1989).

3. I. Glassman (ed.), Combustion, 2nd Edition, Academic Press, New York (1987). ISBN: 0-12-285851-4.

4. A. J. Colussi, F. Zabel, and S. W. Benson, “The very low-pressure pyrolysis of phenyl ethyl ether, phenyl allyl ether, and benzyl methyl ether and the enthalpy of formation of the phenoxy radical,” Int. J. Chem. Kinet. 9(2), 161-178 (1977).

5. C.-Y. Lin, and M. C. Lin, “Thermal decomposition of methyl phenyl ether in shock waves: The kinetics of phenoxy radical reactions,” J. Phys. Chem. 90(3), 425-431 (1986).

6. C. A. Taatjes, D. L. Osborn, T. M. Selby, G. Meloni, A. J. Trevitt, E. Epifanovsky, A. I. Krylov, B. Sirjean, E. Dames, and H. Wang, “Products of the benzene + O (3P) reaction,” J. Phys. Chem. A 114(9), 3355-3370 (2010).

7. A. Burcat, and M. Dvinyaninov, “Detailed kinetics of cyclopentadiene decomposition studied in a shock tube,” Int. J. Chem. Kinet. 29(7), 505-514 (1997).

8. “Hazard Prevention and Control in the Work Environment: Airborne Dust,” World Health Organization (2015).

9. M. Frenklach, “Reaction Mechanism of Soot Formation in Flames,” PCCP 4(11), 2028-2037 (2002).

10. L. V. Moskaleva, A. M. Mebel, and M. C. Lin, “The CH3 + C5H5 reaction: A potential source of benene at high temperatures,” P. Combust. Inst. 26(1), 521-526 (1996).

11. S. Sharma, and W. H. Green, “Computed Rate Coefficients and Product Yields for c-C5H5 + CH3 → Products,” J. Phys. Chem. A 113(31), 8871-8882 (2009).

12. C. F. Melius, BAC-MP4 Heats of Formation and Free Energies, Sandia National Laboratories, Livermore, CA (1993).

13. A. W. Jasper, and N. Hansen, “Hydrogen-assisted isomerizations of fulvene to benzene and of larger cyclic aromatic hydrocarbons,” Proc. of the Combustion Institute 34(1), 279-287 (2013).

14. L. A. Curtiss, K. Raghavachari, G. W. Trucks, and J. A. Pople, “Gaussian‐2 theory for molecular energies of first‐and second‐row compounds,” J. Chem. Phys. 94(11), 7221-7230 (1991).

15. J. A. Pople, M. Head-Gordon, D. J. Fox, K. Raghavachari, and L. A. Curtiss, “Gaussian‐1 theory: A general procedure for prediction of molecular energies,” J. Chem. Phys. 90(10), 5622-5629 (1989).

16. L. A. Curtiss, C. Jones, G. W. Trucks, K. Raghavachari, and J. A. Pople, “Gaussian‐1 theory of molecular energies for second‐row compounds,” J. Chem. Phys. 93(4), 2537-2545 (1990).

17. H.-J. Werner, P. J. Knowles, G. Knizia, F. R. Manby, and M. Schütz, “Molpro: a general‐purpose quantum chemistry program package,” Wiley Interdisciplinary Reviews: Computational Molecular Science 2(2), 242-253 (2012).

18. Y. Georgievskii, J. A. Miller, M. P. Burke, and S. J. Klippenstein, “Reformulation and Solution of the Master Equation for Multiple-Well Chemical Reactions,” J. Phys. Chem. A 117(46), 12146-12154 (2013).

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