KINETICS OF THE CATALYTIC DEHYDROCYCLIZATION OF n-HEPTANE

Rohrer, J. C.; Hurwitz, H.; Sinfelt, J. H.

doi:10.1021/j100826a513

Cited by 30 publications

(2 citation statements)

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“…Although reactions involving the loss of hydrogen (dehydrogenation of alkanes to unsaturated products or to aromatics) can occur without hydrogen, the active life of the catalyst is very short under these conditions. Rohrer et al (1961) reported maxima in aromatic yields as a function of hydrogen pressure. Reviews of hydrogen effects on these reactions have been presented by Paa ´l and Menon (1983Menon ( , 1988.…”

Section: Hydrogen Effects On Reforming Reactionsmentioning

confidence: 99%

Some Aspects of the Mechanisms of Catalytic Reforming Reactions

Menon

Paál

1997

Ind. Eng. Chem. Res.

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A brief review is given of the evolution of our ideas on the mechanism of catalytic reforming reactions over the last 40 years. The early bifunctional reaction mechanism, though criticized much, led first to an understanding and optimization of the reforming process and later to several other catalyst and process innovations. Kinetic and tracer studies on model catalysts using single hydrocarbons as reactants and the surface-science approach revealed the finer nuances of the mechanism involved. Simultaneously, the roles of S, Cl, coke, and hydrogen and of a second metal component like Re, Ir, or Sn in the industrial catalyst were also understood to a greater or lesser extent. All these results make the mechanism of reforming reactions a field of fascinating complexity in fundamental and industrial catalysis.

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Section: Hydrogen Effects On Reforming Reactionsmentioning

confidence: 99%

Some Aspects of the Mechanisms of Catalytic Reforming Reactions

Menon

Paál

1997

Ind. Eng. Chem. Res.

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“…The aromatization of n-heptane is an important reforming reaction, especially on supported platinum catalysts, and numerous studies have focused on its activity and product distribution behavior (Ruhrer et al, 1961;Nix and Weisz, 1964;Davies, 1973Davies, , 1974Pines and Nogueira, 1981;Lietz et al, 1984), without reporting the kinetics of n-heptane reforming. However, few comprehensive kinetic studies of the reforming reaction of n-heptane have been published.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Kinetic Models for n-Heptane Reforming on Platinum/Alumina Catalyst

Olafadehan

Susu

Jaiyeola

2008

Petroleum Science and Technology

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The kinetics of the reforming of n-heptane on a platinum/alumina catalyst has been studied in a pulse microcatalytic reactor at a total pressure of 391.8 kPa over a relatively wide temperature range of 420 ı C-500 ı C. The differential and integral methods were used for the kinetic analyses of the reforming reaction. Twenty-nine reaction rate equations of the Langmuir-Hinselwood-Hougen-Watson type, based on molecular and atomic adsorption of hydrogen, were developed. Parameter estimates for the n-heptane reforming reactions were obtained by application of the Nelder-Mead simplex optimization technique to the predicted and observed conversion/production rates of the reaction components. Discrimination among rival kinetic models was based upon physicochemical criteria, analysis of the residuals, and statistical and thermodynamic tests. The rate-determining step was found to be the surface reaction of adsorbed iso-heptane to adsorbed methylcyclohexane with dissociative adsorption of hydrogen on the catalyst surface during dehydrocyclization of iso-heptane to methylcyclohexane. Hence, the surface reaction on the metallic function is ratedetermining for the n-heptane reforming on the Pt/Al 2 O 3 catalyst.

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Dehydrocyclization—Heterogeneous

Paál¹

2010

Encyclopedia of Catalysis

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The formation of aromatic rings from alkanes such as hexane, heptane, octane, and so on (aromatization or dehydrocyclization) on oxide catalysts: chromia, lanthana, metals, such as platinum, palladium, and so on, and nonacidic (Na‐ or Ba‐L zeolite) supports is a “monofunctional” route, catalyzed by the active ingredient itself. A bifunctional route prevails in naphtha reforming (platforming) over Pt on acidic supports (eg, alumina). Interactions of Pt with acidic or alkaline support can be important for aromatization. The metallic function can also catalyze the formation of five‐membered ring(s): C5‐cyclization. The effect of added metallic components resulting in bimetallic catalysts (such as PtRe, PtSn, and so on) as well as the effect of nonmetallic components (Cl, S, C, H) is discussed. Aromatization requiring skeletal rearrangement (eg, of alkylpentane feeds) can also take place. Cyclic hydrocarbons may undergo ring enlargement and ring contraction. The same catalyst may promote the formation of a second ring in alkylcyclopentanes. The buildup of aromatic rings is also possible from smaller molecules (ethane, propane, butane) by dehydrocyclodimerization over bifunctional catalysts, such as ZSM 5 zeolites containing Pt, Zn, but first of all Ga (eg, in the CYCLAR process). Aromatics can be produced even from methane (Mo carbide‐ZSM‐5 or Pd‐Co catalysts).

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KINETICS OF THE CATALYTIC DEHYDROCYCLIZATION OF n-HEPTANE

Cited by 30 publications

References 1 publication

Some Aspects of the Mechanisms of Catalytic Reforming Reactions

Some Aspects of the Mechanisms of Catalytic Reforming Reactions

Mechanistic Kinetic Models for n-Heptane Reforming on Platinum/Alumina Catalyst

Dehydrocyclization—Heterogeneous

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