A comparison of alumina, carbon, and carbon-covered alumina as supports for Ni-Mo-F additives: Carbon deposition and model compound reaction studies

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(91)90311-Q· OSTI ID:5619130

Boorman, P M; Chong, K; Kydd, R A; Lewis, J M ^[1]

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1. Univ. of Calgary, Alberta (Canada)

Fluoride-promoted Ni-Mo catalysts supported on alumina, carbon, and carbon-coveres alumina have been investigated for their activity in cumene cracking, hydrocracking (reduced and sulfided forms), and thiophene HDS. The carbon-covered alumina was prepared by pyrolysis of cyclohexene over either {gamma}-alumina or boehmite and the carbon deposition followed adsorption isotherm-type behavior. The cumene reaction studies indicate that the resulting support system successfully merges the properties of carbon and alumina, possessing improved dehydrogenation-hydrogenation functionality due to carbon and acidic properties due to alumina, such as the generation of Broensted acidity upon fluoride impregnation. In the thiophene HDS reaction the catalyst activities followed the order Al{sub 2} > C-Al{sub 2}O{sub 3} > C, suggesting that alumina, and not carbon, is the superior HDS support at atmospheric H{sub 2} pressure and at the metal loadings used in this study. Carbon deposition onto Ni-Mo-F/Al{sub 2}O{sub 3} catalysts revealed that cyclohexene polymerization is promoted by the metal centers, resulting in multilayer islands on these sites, and not by the fluoride-associated Broensted acid sites. However, the Broensted acid sites do promote coke formation when the polymerization reaction is easier such as for {alpha}-methylstyrene.

• OSTI ID: 5619130
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 128:2; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION ISOTHERMS
ALKENES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AROMATICS
BROENSTED ACIDS
CARBON
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CRACKING
CUMENE
CYCLOALKENES
DEACTIVATION
DECOMPOSITION
DEHYDROGENATION
DEPOSITION
DESULFURIZATION
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROCRACKING
HYDROGEN COMPOUNDS
HYDROGENATION
IMPREGNATION
INORGANIC ACIDS
ISOTHERMS
METALS
MOLYBDENUM
NICKEL
NONMETALS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
POLYMERIZATION
PYROLYSIS
SYNTHESIS
TESTING
THERMOCHEMICAL PROCESSES
THIOPHENE
TRANSITION ELEMENTS