The reaction of cyclohexane with H-atoms: A shock tube and modeling study

✍ Scribed by Sebastian Peukert; Clemens Naumann; Marina Braun-Unkhoff; Uwe Riedel

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 767 KB
• Volume: 44
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20595

✦ Synopsis

The present work deals with experimental investigations on the bimolecular reaction of H-atoms with cyclohexane (cC 6 H 12 ). Iodoethane (C 2 H 5 I) was used as an in situ source for H-atoms to investigate the bimolecular reaction. As the reaction of cC 6 H 12 with H-atoms yields H 2 and cyclohexyl radicals (cC 6 H 11 ), the mechanism of the thermal decomposition of cC 6 H 11 is of fundamental importance for the interpretation of the experiments. Therefore, also the thermal decomposition of 1-hexene-6-yl (16-C 6 H 11 ) was analyzed due to the assumption that cC 6 H 11 almost exclusively isomerizes to 16-C 6 H 11 . 6-Iodo-1-hexene (16-C 6 H 11 I) was used as a precursor molecule for the generation of 16-C 6 H 11 radicals. The experiments were carried out in a stainless steel shock tube. For the reaction of cC 6 H 12 molecules with H-atoms, the measurements were performed over a temperature range of 1050-1190 K, at pressures ranging from 1.8 to 2.5 bar; the 16-C 6 H 11 I experiments were carried out at temperatures between 1060 and 1160 K and pressures around 2.0 bar. Behind reflected shock waves, the H-atom absorption was monitored by atomic resonance absorption spectrometry at the Lyman-α line (121.6 nm). The experiments reveal important aspects about the thermal dissociation of cyclohexyl radicals (cC 6 H 11 ). Concerning the reaction cC 6 H 12 + H → cC 6 H 11 + H 2 (R1), a rate coefficient expression was derived: k R1 (T) = 6.3 × 10 13 exp(-2505 K/T) cm 3 mol -1 s -1 .