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Kinetic study and modeling of the hetero‐homogeneous pyrolysis and oxidation of isobutane around 800 K. Part II. Pyrolysis in pyrex reactors packed with platinum foils or PbO‐treated pyrex rods
Author(s) -
Zils R.,
Martin R.,
Perrin D.
Publication year - 1998
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1998)30:6<439::aid-kin6>3.0.co;2-t
Subject(s) - isobutane , chemistry , platinum , packed bed , pyrolysis , homogeneous , kinetic energy , microreactor , atmospheric temperature range , torr , chemical engineering , hydrogen , analytical chemistry (journal) , thermodynamics , catalysis , organic chemistry , chromatography , physics , quantum mechanics , engineering
Isobutane pyrolysis has been studied at 20–200 torr initial pressures and 773–793 K, in a packed reactor treated with PbO and in a reactor packed with platinum foils. These packings strongly inhibit product formation and this effect is explained by the occurrence of the heterogeneous termination step: $$\rm H\cdot\mathrel{\mathop{\relbar\joinrel\longrightarrow}^{walls}} product$$ at the reactor walls. The reaction has been modeled in the temperature and pressure range on the basis of a kinetic scheme which has been proposed for the homogeneous reaction and step ( w ) with the following values of k w : $$\eqalign{(k_{_{w}})_{_{\rm{PbO}}}&=3.7\ 10^{8}\ \rm{exp} \left[-{9000\over \rm{T}}\right]\rm{S}^{-1}\cr(k_{_{w}})_{_{\rm{Pt}}}&=15000\ \rm{S}^{-1}\ \rm{at\ any\ temperature}\cr}$$ for both types of packing. The corresponding sticking coefficients of hydrogen atoms are: $$\eqalign{\gamma _{_{\rm{PbO}}} &=160\ \rm{exp} \left[-{9000\over \rm{T}}\right]\cr\gamma _{_{\rm{Pt}}} &=0.03\cr}$$ © 1998 John Wiley & Sons, Inc. Int J Chem. Kinet 30: 439–450,1998