Isomerization of Alkyl Aromatic Hydrocarbons

Pitts, P. M.; Connor, J. E.; Leum, L. N.

doi:10.1021/ie50544a035

Cited by 37 publications

(14 citation statements)

References 2 publications

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“…This conclusion agrees with the work of Pitts et al (1955), who showed that xylene isomerizations probably do not require naphthenes (or partially hydrogenated aromatics) as intermediates.…”

Section: Preliminary Experiments Preliminary Experimentssupporting

confidence: 92%

Kinetics of the Gas-Phase Catalytic Isomerization of Xylenes

Corma¹,

Cortés²

1980

Ind. Eng. Chem. Proc. Des. Dev.

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The kinetics of the gas-phase isomerization of xylenes in the presence of hydrogen have been studied in a fixed-bed flow reactor under initial conditions. The study was carried out using a silica-alumina catalyst containing 4 wt % nickel, at 400 to 465 °C and a total pressure of up to 3.95 kg/cm2. The kinetic parameters thus obtained when used iri our mathematical model reproduce the observed product distribution up to equilibrium conversion in an isothermal reactor packed with powdered catalyst. By introducing an effectiveness factor into the model, it is also possible to fit data obtained under similar conditions using a pellet sized catalyst.

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Section: Preliminary Experiments Preliminary Experimentssupporting

confidence: 92%

Kinetics of the Gas-Phase Catalytic Isomerization of Xylenes

Corma¹,

Cortés²

1980

Ind. Eng. Chem. Proc. Des. Dev.

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“…Ethylbenzene does not isomerize over acidic catalysts (Lien, 1954). As was shown by Pitts et al (1955), isomerization of ethylbenzene proceeds via hydrogenated intermediates over bifunctional catalysts. Recently, Gnep and Guisnet (1977) reported that the main product of ethylbenzene isomerization over weakly acidic Pt/Al203-F catalysts is o-xylene, while m-and p-xylene are formed in smaller amounts.…”

Section: Introductionmentioning

confidence: 70%

Reaction Mechanism of Ethylbenzene Isomerization

Röbschläger¹,

Christoffel²

1979

Ind. Eng. Chem. Prod. Res. Dev.

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Isomerization of ethylbenzene in the gaseous phase over bifunctional Pt/AI^a nd Pt-zeolite catalysts was investigated in a microcatalytic fixed bed reactor using the pulse method. Over the Pt/Al203 catalyst, where the carrier displays only weak acidity, xylenes are formed from ethylbenzene mainly via the route ethylbenzene-ethylcyclohexene-1,2-methylethylcyclopentene-1,2-dimethylcyclohexene-o-xylene, which corresponds to predictions from a bifunctional mechanism in which skeletal rearrangements of tertiary carbocations only are considered to be the rate-determining steps. Over Pt-zeolite catalysts with higher acidity, skeletal isomerizations in which secondary carbocations are involved contribute-in addition to the route mentioned above-to the measured product distributions.

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“…Liquid phase studies have generally been made with homogeneous acidic halide catalysts (Allen and Yats, 1959; Brown and Jungk, 1959; Kemp, 1950;McCaulay, 1964) which suffer from corrosion and recovery problems. Vapor phase reactions over heterogeneous silica-alumina and dual-function type catalysts avoid these problems but lead to coke formation and lower yield of desired products because of the higher temperature required (Hanson and Engel, 1967; Silvestri and Prater, 1964; Ciapetta and Hunter, 1953; Pitts et al, 1955). High activity of a large number of zeolites relative to silica-alumina catalyst was reported by Hansford and Ward (1969).…”

Section: Introductionmentioning

confidence: 99%