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Extension of the single-event microkinetic model to alkyl substituted monoaromatics hydrogenation on a Pt catalyst

Tapan Bera UGent, Joris Thybaut UGent and Guy Marin UGent (2012) ACS CATALYSIS. 2(7). p.1305-1318
abstract
The Single-Event Micro Kinetic (SEMK) methodology, which had been successfully applied to benzene hydrogenation on a Pt catalyst, has now been extended toward substituted monoaromatics, that is, toluene and o-xylene. The single event concept Combined with thermodynamic constraints. allowed to significantly reduce the number of adjustable parameters. In addition to the number of unsaturated nearest neighbor carbon atoms, H-atom addition rate and equilibrium coefficients were assumed to depend on the carbon atom type, that is, secondary or tertiary. This leads to three additional :reaction families compared to benzene hydrogenation: Gas. phase toluene and o-xylene hydrogenation experiments were performed on 0.5 wt % Pt/ZSM-22 in a temperature range from 423 to 498 K, a total pressure range from 1 to 3 MPa, H-2 inlet partial pressures between 100 and 600 kPa and aromatic inlet partial pressures between 10 and 60 kPa. A simultaneous regression of the :SEMK,Model to an experimental data set consisting of 39 toluene and 37 o-xylene hydrogenation experiments resulted in activation energies of H additions to tertiary:carbon:atoms:that are 10.5 kJ mol(-1) higher than to secondary carbon atoms. This can be related to the steric hindrance experienced during H addition to a carbon atom bearing a substituent. The presence of a substituent on the aromatic king was found not to affect the Chemisorption enthalpies. The reaction path analysis has been carried out via differential contribution analysis and identified that the hydrogenation first, occurs at secondary carbon atoms, prior to the hydrogenation of the tertiary carbon atoms in the hydrogenation Sequence. This is in line with the distribution of hydrocarbon species on the catalyst surface
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
FUNDAMENTAL KINETIC-MODEL, LIQUID-PHASE HYDROGENATION, NICKEL-SILICA CATALYST, PT/US-Y ZEOLITES, BENZENE HYDROGENATION, AROMATIC-HYDROCARBONS, REACTION NETWORKS, RATE PARAMETERS, COKE FORMATION, USY ZEOLITE, hydrogenation, monoaromatics, toluene, o-xylene, platinum, noble metal, single event microkinetic modeling
journal title
ACS CATALYSIS
ACS Catal.
volume
2
issue
7
pages
1305 - 1318
Web of Science type
Article
Web of Science id
000306297900002
JCR category
CHEMISTRY, PHYSICAL
JCR impact factor
5.265 (2012)
JCR rank
23/133 (2012)
JCR quartile
1 (2012)
ISSN
2155-5435
DOI
10.1021/cs300051j
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
2969508
handle
http://hdl.handle.net/1854/LU-2969508
date created
2012-08-07 15:52:24
date last changed
2013-08-01 00:30:33
@article{2969508,
  abstract     = {The Single-Event Micro Kinetic (SEMK) methodology, which had been successfully applied to benzene hydrogenation on a Pt catalyst, has now been extended toward substituted monoaromatics, that is, toluene and o-xylene. The single event concept Combined with thermodynamic constraints. allowed to significantly reduce the number of adjustable parameters. In addition to the number of unsaturated nearest neighbor carbon atoms, H-atom addition rate and equilibrium coefficients were assumed to depend on the carbon atom type, that is, secondary or tertiary. This leads to three additional :reaction families compared to benzene hydrogenation: Gas. phase toluene and o-xylene hydrogenation experiments were performed on 0.5 wt \% Pt/ZSM-22 in a temperature range from 423 to 498 K, a total pressure range from 1 to 3 MPa, H-2 inlet partial pressures between 100 and 600 kPa and aromatic inlet partial pressures between 10 and 60 kPa. A simultaneous regression of the :SEMK,Model to an experimental data set consisting of 39 toluene and 37 o-xylene hydrogenation experiments resulted in activation energies of H additions to tertiary:carbon:atoms:that are 10.5 kJ mol(-1) higher than to secondary carbon atoms. This can be related to the steric hindrance experienced during H addition to a carbon atom bearing a substituent. The presence of a substituent on the aromatic king was found not to affect the Chemisorption enthalpies. The reaction path analysis has been carried out via differential contribution analysis and identified that the hydrogenation first, occurs at secondary carbon atoms, prior to the hydrogenation of the tertiary carbon atoms in the hydrogenation Sequence. This is in line with the distribution of hydrocarbon species on the catalyst surface},
  author       = {Bera, Tapan and Thybaut, Joris and Marin, Guy},
  issn         = {2155-5435},
  journal      = {ACS CATALYSIS},
  keyword      = {FUNDAMENTAL KINETIC-MODEL,LIQUID-PHASE HYDROGENATION,NICKEL-SILICA CATALYST,PT/US-Y ZEOLITES,BENZENE HYDROGENATION,AROMATIC-HYDROCARBONS,REACTION NETWORKS,RATE PARAMETERS,COKE FORMATION,USY ZEOLITE,hydrogenation,monoaromatics,toluene,o-xylene,platinum,noble metal,single event microkinetic modeling},
  language     = {eng},
  number       = {7},
  pages        = {1305--1318},
  title        = {Extension of the single-event microkinetic model to alkyl substituted monoaromatics hydrogenation on a Pt catalyst},
  url          = {http://dx.doi.org/10.1021/cs300051j},
  volume       = {2},
  year         = {2012},
}

Chicago
Bera, Tapan, Joris Thybaut, and Guy Marin. 2012. “Extension of the Single-event Microkinetic Model to Alkyl Substituted Monoaromatics Hydrogenation on a Pt Catalyst.” Acs Catalysis 2 (7): 1305–1318.
APA
Bera, T., Thybaut, J., & Marin, G. (2012). Extension of the single-event microkinetic model to alkyl substituted monoaromatics hydrogenation on a Pt catalyst. ACS CATALYSIS, 2(7), 1305–1318.
Vancouver
1.
Bera T, Thybaut J, Marin G. Extension of the single-event microkinetic model to alkyl substituted monoaromatics hydrogenation on a Pt catalyst. ACS CATALYSIS. 2012;2(7):1305–18.
MLA
Bera, Tapan, Joris Thybaut, and Guy Marin. “Extension of the Single-event Microkinetic Model to Alkyl Substituted Monoaromatics Hydrogenation on a Pt Catalyst.” ACS CATALYSIS 2.7 (2012): 1305–1318. Print.