Effect of olefins on the thermal decomposition of propane part I. The model reaction

✍ Scribed by A. Dombi; P. Huhn

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 495 KB
• Volume: 18
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550180208

✦ Synopsis

Study of the thermal decomposition of propane at very low conversions in the temperature range 760-830 K led to refinement of the mechanism of the reaction.

The quotient u C H ~+ C ~H ~/ I J H ~+ C ~H ~

characterizing the two decomposition routes connected with the 1-and 2-propyl radicals proved to depend linearly on the initial propane concentration. This suggested the occurrence of intermolecular radical isomerization:

in competition with decomposition of the 2-propyl radical:

The linearity led t o the conclusion t h a t the selectivity of H-abstraction from the methyl and methylene groups by the methyl radical is practically the same as that by the H atom. The temperature-dependence of this selectivity (p = kCH3/kCH2) was given by exp(-7.24 f 0.45 kJ mol-*/RT). = 3 k k = f . = 100262003 k4 k* Further evaluation of the dependence gave the Arrhenius representation --' 7 -10-5.97?034 exp(ll5 ? 5.1 kJ mol-'/RT) mol-'dm3

for the ratio of the rate coefficients of the above isomerization and decomposition reactions.

Steady-state treatment resulted in the rate equation of the process, comparison of which with measurements gave further Arrhenius dependences. k6