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Berger, Rob J.; Stitt, E. Hugh; Marin, Guy; Kapteijn, Freek; Moulijn, Jacob A.

doi:10.1023/a:1011928218694

Cited by 142 publications

(89 citation statements)

References 23 publications

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“…35,36 As hydrogenation occurred on the external crystallite surface, intracrystalline diffusion is not relevant. 16 The operating conditions, together with reactant and reactor type were selected to measure intrinsic kinetics, free from transport limitations and reactor flow pattern nonidealities.…”

Section: Methodsmentioning

confidence: 99%

Extension of the Single-Event Microkinetic Model to Alkyl Substituted Monoaromatics Hydrogenation on a Pt Catalyst

2012

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The Single-Event MicroKinetic (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 ring 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.

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Section: Methodsmentioning

confidence: 99%

Extension of the Single-Event Microkinetic Model to Alkyl Substituted Monoaromatics Hydrogenation on a Pt Catalyst

2012

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“…[36] The amount of intermediates that lead to CH 4 is calculated from t CH4,s and the outlet flow of CH 4 [Eq. (9) Modeling By using well-known criteria, [37] the absence of heat and mass transfer limitations were checked. This allowed to use ar ather simple model that only takes into account the chemical kinetics.…”

Section: Ssitka Data Treatmentmentioning

confidence: 99%

Measurement of the Influence of the Microstructure of Alumina‐Supported Cobalt Catalysts on their Activity and Selectivity in Fischer–Tropsch Synthesis by using Steady‐State and Transient Kinetics

et al. 2017

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Five alumina‐supported Co catalysts with different particle sizes and structures were synthesized. The catalysts showed different activities during long‐term Fischer–Tropsch experiments. Steady‐state isotopic transient kinetic analysis (SSITKA) 12CO/H2→13CO/H2 experiments were performed during these long‐term runs. The number of active sites for CO adsorption and activation was estimated through the summation of all surface intermediates derived from the SSITKA results. Rather than comparing turnover frequencies, a kinetic analysis was performed. A simple kinetic rate equation based on the in situ number of active sites described the steady‐state CO conversion over the five catalysts adequately. Thus the difference in the catalytic performance could not be attributed to a difference in particle size, phase orientation (face‐centered cubic or hexagonal close packed), or Pt‐promotion effect but instead was only because of the number of reduced Co atoms exposed during the reaction. Similarly, the selectivity depended on the CO conversion level and temperature and not on the catalyst structure.

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“…The reparameterization of Arrhenius expression was applied to reduce the interdependency between the activation energy and the pre-exponencial factor, which diminishes the fitting procedure (Berger et al, 2001):…”

Section: Reaction Temperaturementioning

confidence: 99%

Kinetics of the Wet Oxidation of Phenol over an Fe/Activated Carbon Catalyst

Quintanilla

Casas

Rodriquez

et al. 2007

International Journal of Chemical Reactor Engineering

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Wet oxidation of phenol over an Fe/activated carbon catalyst has been studied in a trickle-bed reactor in the following operational window: inlet C phenol=0.5 and 1 g/L, T=100-127• C, PT=3-8 atm, W=0-4.8 g, QL=0.125-2 mL/min and QO2=91.6 NmL/min. The experiments were carried out in the absence of mass transfer limitations. Oxidation and mineralization reactions of phenol are proven to take place on the catalyst surface through a heterogeneous mechanism. Due to the complexity of the phenol oxidation route, simple reaction schemes have been assumed by lumping the intermediate species and generalized kinetic models for phenol and TOC abatement have been proposed. Two kinetic expressions, a power law rate and a Langmuir-Hinshelwood type rate expression, have been considered but only a convergence with statistically reliable parameters was found for the former model. A power law model with first order for phenol and 0.74 for oxygen and apparent activation energy of 74 kJ/mol described the experimental results in the oxidation of phenol well. Mineralization of phenol (TOC abatement) was described by a similar rate expression and takes into account the presence of refractory species such as the low molecular weight acids formed upon phenol oxidation.

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Untitled

Cited by 142 publications

References 23 publications

Extension of the Single-Event Microkinetic Model to Alkyl Substituted Monoaromatics Hydrogenation on a Pt Catalyst

Extension of the Single-Event Microkinetic Model to Alkyl Substituted Monoaromatics Hydrogenation on a Pt Catalyst

Measurement of the Influence of the Microstructure of Alumina‐Supported Cobalt Catalysts on their Activity and Selectivity in Fischer–Tropsch Synthesis by using Steady‐State and Transient Kinetics

Kinetics of the Wet Oxidation of Phenol over an Fe/Activated Carbon Catalyst

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