Reactions of benzene and alkylbenzenes with deuterium over molybdena-alumina and alumina catalysts

Journal Article · Sun Nov 01 00:00:00 EST 1987 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(87)90165-5· OSTI ID:5204498

Redey, A; Hall, W K

The reactions of D/sub 2/ with aromatic systems were studied. Benzene did not hydrogenate at atmospheric pressure. On the other hand, exchange between benzene-d/sub 0/ and D/sub 2/ was facile at 70/sup 0/C and 1 atm over reduced (eMo approx. = 1.7) and at 200/sup 0/C over sulfided (eMo approx. = 3.0) catalysts. The exchange reaction also occurred over the alumina support at an intermediate rate. Over alumina the exchange at 70/sup 0/C was stepwise (M = k/sub theta/k/sub 0/ approx. = 1.0), but as the temperature and hence k/sub 0/ increased, multiple exchange (M greater than or equal to 2.0) set in. The usual tests showed that this was not a result of a pore diffusion limitation. The rate of exchange of C/sub 6/D/sub 6/ with the alumina hydroxyl groups increased sharply as the temperature was increased to near 200/sup 0/C in a way which mimicked the increase in M. Thus, the increase in multiplicity may be ascribed to the opening of new pathways for exchange. The much faster rates and higher values of M obtained over the reduced catalysts than over the sulfided ones, coupled with the results of poisoning experiments using NO and CO/sub 2/ (both of which drastically reduced the rates and returned the exchange process to M approx. = 1.0), demonstrated that with the reduced catalyst both portions of the surface act synergistically. The results may be rationalized by the supposition that exchange occurs on the alumina support and that hydrogen may spill-over on reduced catalysts, but not on sulfided ones. In the exchange reactions, alkylaromatics were found to have higher rates for ring than for side chain hydrogens

• Research Organization: Univ. of Pittsburgh, PA (USA)
• OSTI ID: 5204498
• Journal Information: J. Catal.; (United States), Vol. 108:1
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
01 COAL, LIGNITE, AND PEAT
ALUMINIUM OXIDES
CATALYTIC EFFECTS
BENZENE
HYDROGENATION
MOLYBDENUM
CATALYSTS
CHEMICAL REACTION KINETICS
COAL LIQUEFACTION
COMPARATIVE EVALUATIONS
DESULFURIZATION
DEUTERIUM
ISOTOPIC EXCHANGE
REDUCTION
SULFIDATION
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
ALUMINIUM COMPOUNDS
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
LIQUEFACTION
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
STABLE ISOTOPES
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENTS
020400* - Petroleum- Processing
010405 - Coal
Lignite
& Peat- Hydrogenation & Liquefaction
010402 - Coal
Lignite
& Peat- Purification & Upgrading