The effects of pressure on the hydrogenation of benzene and naphthalene over reduced and sulfided molybdena-alumina catalysts

Journal Article · Sun Oct 01 00:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90184-X· OSTI ID:6842548

Redey, A; Hall, W K ^[1]

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1. Univ. of Pittsburgh, PA (USA)

In earlier work it is shown that benzene could not be hydrogenated under 1 atm total pressure over the same reduced or sulfided molybdena-alumina catalyst which was hyperactive for olefin hydrogenation after similar pretreatment. Hydrogenation became detectable, however, after reduction at 800 C where the average oxidation number (O.N.) was 1.3 (e/Mo = 4.7) and the reaction became facile after reduction at 900 C where metallic molybdenum was evidently present (O.N. = 0.9); others have also reached this latter conclusion. Catalysts reduced below 600 C, as is the customary procedure, have O.N. {approx}4; they contain mainly Mo{sup 4+} together with small amounts of Mo{sup 5+}, balanced by some lower valence states, but no evidence of Mo{sup 0} or metallic molybdenum has been expected or reported. It was suggested, therefore, that the hydrogenation of benzene carried out with P{sub H{sub 2}} {approximately} 1 atm might be used as a sensitive diagnostic test for the presence of this metal or conceivably some other low-valence state. In the present work these results have been extended to much higher hydrogen pressures. In spite of the fact that benzene could not be hydrogenated on conventionally prepared catalysts (reduced at T < 600 C), exchange between D{sub 2} and the benzene hydrogens occurred at 70 C. It was shown, however, that this process took place largely on the alumina portion of the surface although it was synergistically influenced by the dissociation of D{sub 2} on the molybdena sites. The exchange reaction could be effectively quenched by the chemisorption of CO{sub 2} prior to reaction. CO{sub 2} has been shown to chemisorb selectively on the alumina portion of the surface.

• OSTI ID: 6842548
• Journal Information: Journal of Catalysis; (USA), Vol. 119:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
BENZENE
HYDROGENATION
MOLYBDENUM
CATALYTIC EFFECTS
MOLYBDENUM SULFIDES
NAPHTHALENE
ALUMINIUM OXIDES
CATALYST SUPPORTS
CHEMICAL PREPARATION
CHEMICAL REACTORS
DEUTERIUM
IMPREGNATION
OXIDATION
PRESSURE DEPENDENCE
REDUCTION
SULFIDATION
SURFACE PROPERTIES
ALUMINIUM COMPOUNDS
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
CONDENSED AROMATICS
ELEMENTS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
METALS
MOLYBDENUM COMPOUNDS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
STABLE ISOTOPES
SULFIDES
SULFUR COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
020400* - Petroleum- Processing