A TAP reactor investigation of C[sub 6] reforming on nonacidic and acidic supported metal catalysts

Journal Article · Wed Jun 01 00:00:00 EDT 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1172· OSTI ID:7275829

Lafyatis, D S; Froment, G F; Pasau-Claerbout, A; Derouane, E G ^[1]

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1. Universiteit Gent (Belgium) Universitaires Notre-Dame de la Paix, Namur (Belgium)

The reforming of C[sub 6] hydrocarbons on Pt/Mg(Al)O, Pt/K-L, Pd/Mg(Al)O, and Pt-Re/Al[sub 2]O[sub 3] (sulfided and unsulfided forms) has been investigated using the temporal analysis of products (TAP) reactor. Pulse experiments with several different pure C[sub 6] feeds were performed in a continuous flow of H[sub 2] at a pressure of 1 bar and temperatures between 400 and 510[degrees]C. Under these conditions the reaction network for all of the catalysts appeared to occur by a monofunctional metal pathway: methylpentane [yields] methylcyclopentane [yields] n-hexane [yields] benzene. Evidence of partially dehydrogenated linear C[sub 6] molecules as intermediates between n-hexane and benzene was also obtained. Turnover frequencies and benzene selectivities for the Pt/Mg(Al)O and the Pt/KL catalysts were comparable. For the Pd/Mg(Al)O catalyst the selectivity to benzene was higher and the turnover frequency was lower. Because the TAP technique reflects only the activity of truly active catalytic sites, the turnover frequencies from this study (10-12 sec[sup [minus]1] at 425[degrees]C on Pt) are higher than generally reported in the literature. Previous investigations of the Pt-Re/Al[sub 2]O[sub 3] catalyst under industrial conditions have shown that the bifunctional mechanism was dominant. The monofunctional mechanism found here implies the existence of two dehydrocyclization pathways on these catalysts: a monofunctional metal pathway favored at low pressures, and a bifunctional pathway which is dominant at higher pressures. 34 refs., 11 figs., 5 tabs.

• OSTI ID: 7275829
• Journal Information: Journal of Catalysis; (United States), Vol. 147:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
02 PETROLEUM
ALKANES
CATALYTIC REFORMING
ALUMINIUM OXIDES
CATALYTIC EFFECTS
MAGNESIUM OXIDES
PALLADIUM
PLATINUM
PLATINUM ALLOYS
RHENIUM ALLOYS
CATALYST SUPPORTS
CATALYSTS
DEHYDROCYCLIZATION
HETEROGENEOUS CATALYSIS
REACTION INTERMEDIATES
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
ALUMINIUM COMPOUNDS
CATALYSIS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
HYDROCARBONS
MAGNESIUM COMPOUNDS
METALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METAL ALLOYS
PLATINUM METALS
REFORMER PROCESSES
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties
020400 - Petroleum- Processing