Déshydrogénation du méthylcyclohexane sur le catalyseur industriel Pt-Sn/Al2O3

Chaouki, Jamal; Touzani, A.; Klvana, D.; Bélanger, G.; Bournonville, J.P.

doi:10.2516/ogst:1988053

Cited by 14 publications

(11 citation statements)

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“…systematic benchmark by S. Gautier et al [87], showing that PBE-dDsC is one of the best compromise for predicting adsorption energies of aromatics and unsaturated HCs on Pt (111).…”

Section: Total Energy Calculationsmentioning

confidence: 99%

Dehydrogenation mechanisms of methyl-cyclohexane on γ-Al2O3 supported Pt13: Impact of cluster ductility

Zhao

Chizallet

Sautet

et al. 2019

Journal of Catalysis

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By using density functional theory (DFT) and ab initio molecular dynamics, we investigate the dehydrogenation reactivity of 13 atoms platinum cluster supported on the alumina (100) surface. We provide a detailed free energy profile and structural analysis of the dehydrogenation mechanisms of methyl-cyclohexane (MCH) into toluene. We highlight the quantitative impact of dispersion corrections on the free energy profile and on the adsorption configurations of the intermediates exhibiting a dual interaction with the cluster and with the alumina surface. During the step by step dehydrogenation of MCH, several reconstructions of the Pt cluster and hydrogen migrations occur. Due to the cluster ductility, they are moderately activated and provide optimal active sites catalyzing the C-H bond cleavages. According to a preliminary kinetic analysis based either on energetic spans or on activation free energies of elementary steps, we found that many states and/or steps may be considered as determining ones. This may explain some diverging interpretations brought by previous experimental kinetic studies. We finally discuss how the cluster ductility challenges the historical concept of structure sensitivity/insensitivity for a given reaction in the case of nanometer-size metallic clusters dispersed on a support.

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“…systematic benchmark by S. Gautier et al [87], showing that PBE-dDsC is one of the best compromise for predicting adsorption energies of aromatics and unsaturated HCs on Pt (111).…”

Section: Total Energy Calculationsmentioning

confidence: 99%

Dehydrogenation mechanisms of methyl-cyclohexane on γ-Al2O3 supported Pt13: Impact of cluster ductility

Zhao

Chizallet

Sautet

et al. 2019

Journal of Catalysis

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“…In support of the above findings, the literature reveals that Touzani et al, 13 Van Trimpont et al, 15 Chaouki et al, 17 Chai et al, 19 and Usman et al 9,26 followed the single‐site surface reaction mechanism in their work. When considering reaction intermediates in the reaction scheme, Touzani et al, 13 Van Trimpont et al, 15 Chaouki et al, 17 and Usman et al 9 found the elementary step “the loss of first molecular hydrogen” controls the rate of the deactivation reaction. Corma et al 33 and Garcia de la Banda et al 34 for the Pt/zeolite catalyst also observed the loss of first molecular hydrogen to be the rate‐determining step.…”

Section: Resultsmentioning

confidence: 57%

“…The kinetics of the MCH dehydrogenation reaction over Pt‐loaded alumina catalyst has been studied by a number of investigators 7‐9,10‐27 . The pioneering work was conducted by Sinfelt et al 11 who, for the dehydrogenation reaction, proposed a two‐step nonequilibrium adsorption reaction mechanism.…”

Section: Introductionmentioning

confidence: 99%

An exclusive kinetic model for the methylcyclohexane dehydrogenation over alumina‐supported Pt catalysts

Akram

Aslam

AlHumaidan

et al. 2020

Int J of Chemical Kinetics

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The experimental data of six different types of Pt-containing alumina catalysts are used to study the detailed and rigorous kinetics of the methylcyclohexane dehydrogenation reaction. A large number of kinetic rate equations were formulated using the power law kinetics and the Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetics, which were tested against the experimental data. For each catalyst, the elementary reaction step "the loss of first molecular hydrogen" in the LHHW single-site surface reaction mechanism was observed to be the rate-determining step. The form of the kinetic rate model developed in the study is believed to be applicable to any Pt-loaded alumina catalyst. K E Y W O R D Sdehydrogenation, Langmuir-Hinshelwood-Hougen-Watson kinetics, methylcyclohexane, organic hydride, Pt catalystInt J Chem Kinet. 2020;52:415-449.

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“…Taking into consideration the reaction intermediates, i.e. methylcyclohexene and methylcyclohexadiene, Touzani et al [14], Chaouki et al [16], Van Trimpont et al [15], Corma et al [13], García de la Banda et al [18], and Usman et al [9] have found the step loss of the first hydrogen molecule (to form methylcyclohexene from MCH) to be a suitable reaction step in fitting their respective experimental data. Moreover, Blakely and Somorjai [21] reasoned that, for the dehydrogenation reaction of cyclohexane to benzene on a platinum single-crystal surface, the loss of the first hydrogen molecule is the rate controlling step and Saeys et al [22] have come up with the same result while using DFT (density functional theory) for the cyclohexane dehydrogenation reaction over a Pt single crystal.…”

Section: Development Of Rate Equationsmentioning

confidence: 99%

Associative Adsorption Kinetics: A Novel Kinetic Model for the Dehydrogenation of Methylcyclohexane

Akram

Munir

Usman

2014

Progress in Reaction Kinetics and Mechanism

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Methylcyclohexane (MCH) dehydrogenation is an important reforming reactionand is considered as a model naphthene dehydrogenation reaction. An increase in the rate of this reaction with the addition of hydrogen at low pressures has been observed by various researchers in the field. This enhancement in rate is described, in the present study, using the concept of associative adsorption of MCH with hydrogen in Langmuir -Hinshelwood -Hougen -Watson singlesite and dual-site surface reaction mechanisms. The various rate equations developed on these bases are tested against the experimental data of Usman over Pt/Al 2 O 3 and the best-fit rate model is presented. An activation energy of 52.0 kJ mol -1 is obtained for the best-fit rate model.

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Déshydrogénation du méthylcyclohexane sur le catalyseur industriel Pt-Sn/Al2O3

Cited by 14 publications

References 0 publications

Dehydrogenation mechanisms of methyl-cyclohexane on γ-Al2O3 supported Pt13: Impact of cluster ductility

Dehydrogenation mechanisms of methyl-cyclohexane on γ-Al2O3 supported Pt13: Impact of cluster ductility

An exclusive kinetic model for the methylcyclohexane dehydrogenation over alumina‐supported Pt catalysts

Associative Adsorption Kinetics: A Novel Kinetic Model for the Dehydrogenation of Methylcyclohexane

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