Direct observation of the rate of H-atom formation in the thermal decomposition of Ortho-, Meta-, and Para-xylene behind shock waves between 1300 and 1800 K
✍ Scribed by I. Da Costa; R.A. Eng; A. Gebert; H. Hippler
- Book ID
- 104270706
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 198 KB
- Volume
- 28
- Category
- Article
- ISSN
- 1540-7489
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✦ Synopsis
The rate of H-atom formation in the thermal decomposition of o-, m-, and p-xylene was studied behind reflected shock waves between 1300 and 1800 K and at pressures of 1.6 to 4 bar by using atomic resonance absorption spectroscopy at 121.6 nm. For the thermal decomposition of p-xylene, m-xylene, and o-xylene
the following rate constants were determined: k 1 ס 1 ן 10 16 exp(083מ kJ mol 1מ /RT) s 1מ , k 2 ס 1 ן 10 16 exp(283מ kJ mol 1מ /RT) s 1מ , and k 3 ס 1 ן 10 16 exp(873מ kJ mol 1מ /RT) s 1מ . The rate constants are all close to the high-pressure limit, and the accuracy was estimated to be 30%. The H-atom-concentration time profiles were modeled using a simple mechanism in which the parallel C-C bond split, and secondary reactions have been taken into account. We found that within our experimental conditions, the C-C bond scission contributes about 15% to the overall decomposition rate constant of the xylenes.