The reactions of phenyl radical (C6H5) are of growing technological and scientific interest. A better understanding of phenyl radical addition to unsaturated hydrocarbons is of great practical interest because it is believed to be an essential component in both soot and fullerene formation. In this study, the rate of phenyl radical addition to butadiene was measured, and the potential surface of the reaction C6H5 + C4H6 was explored using quantum chemistry with the B3LYP density functional. Vibrational analysis allowed the determination of thermodynamic data and deduction of high-pressure-limit rate constants via transition- state theory. The pressure and temperature dependences of this chemically activated reaction were computed using a weak collision master equation analysis. The comparison of the predictions for the C6H5 + C4H6 system with experimental data showed good agreement. The rate constant for disappearance of phenyl radical was found to be (3.16 ± 0.29)×1012 cm3/mol-s exp[-(870 ± 30)/T] over the temperature range 298-450 K. The dominant product at low temperature is the initial adduct, 4-phenylbuten- 3-yl. Around 1000 K, the dominant product is phenyl butadiene formed from the chemically activated adduct, even at 10 atm. Above about 1400 K, bimolecular H-abstraction to form benzene is the most important process. Other products such as 1,4-dihydronaphthalene are much less important.
|Number of pages||8|
|Journal||Proceedings of the Combustion Institute|
|State||Published - 1 Jan 2005|
|Event||30th International Symposium on Combustion - Chicago, IL, United States|
Duration: 25 Jul 2004 → 30 Jul 2004
- Master equation