Kinetics of the cyclopentadiene decay and the recombination of cyclopentadienyl radicals with H-atoms: Enthalpy of formation of the cyclopentadienyl radical

✍ Scribed by K. Roy; M. Braun-Unkhoff; P. Frank; Th. Just

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 207 KB
• Volume: 33
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.10005

✦ Synopsis

Abstract

The recombination of c‐C~5~H~5~ with H‐atoms has been studied behind reflected shock waves. The obtained rate coefficients are almost independent of temperature and were found to be k~rec~ = 2.6 × 10^14^ cm^3^ mol^−1^ s^−1^ for pressures around 2 bar in the temperature range between 1150 and 1500 K. Together with rate coefficients for the dissociation, obtained in an earlier work (Roy et al., Proc Combust Inst 1998, 27, 329–336) at pressures and temperatures close to those applied in the present work, we calculated equilibrium constants K~c~(T) for C~5~H~6~ ⇌ c‐C~5~H~5~ + H. A “third law” analysis was performed. Data for the enthalpy of formation of cyclopentadienyl DH~f,0~ = 65.4 ± 1 kcal mol^−1^ and DH~f,298~ = 62.5 ± 1 kcal mol^−1^ were derived, respectively. The analysis was based upon new results on the entropy of cyclopentadienyl, recently calculated by Kiefer et al. (J phy chem, in press). Finally, our measured data were subjected to a fall‐off analysis. The simulation turned out very satisfactorily. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 821–833, 2001