Steady-state and isotopic transient kinetics of benzene hydrogenation on nickel catalysts

Journal Article · Mon Jun 01 00:00:00 EDT 1987 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(87)90069-8· OSTI ID:5394000

Mirodatos, C; Dalmon, J A; Martin, G A

By combining steady-state and isotopic transient experiments which provide both apparent and true kinetic parameters, the authors propose a modeling of the benzene hydrogenation reaction over nickel catalysts at low temperature (below 400 K). The metal surface is shown to be covered mainly with adsorbed hydrogen; only a very small fraction of the surface (about 1%) is covered with reacting intermediates. From the physically significant parameters thus determined, the authors arrive at the rate equation r = k/sub 0/e/sup -E/sub 0//RT/(1 - theta/sub H/)/sup x/P/sub H/P/sub B//sup epsilon/, where E/sub 0/ = 33 +/- 4 kJ/mol, theta/sub H/-the surface coverage with hydrogen, X = 4 +/- 1, and P/sub H/ and P/sub B/-partial pressures of hydrogen and benzene, respectively. The rate-limiting step can be described as a two-body process between (i) the active site, an ensemble of about four adjacent nickel atoms occupied by a chemisorbed benzene molecule, and (ii) a molecular hydrogen species. The concentration of the active ensembles is monitored by the hydrogen coverage, the latter being influenced little by the reservoir of loosely adsorbed benzene which coats and feeds the catalytic surface.

• Research Organization: l'Universite Claude Bernard Lyon I, France
• OSTI ID: 5394000
• Journal Information: J. Catal.; (United States), Vol. 105:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
BENZENE
HYDROGENATION
NICKEL
CATALYTIC EFFECTS
CATALYSIS
CHEMICAL REACTION KINETICS
CHEMISORPTION
HYDROGEN
KINETIC EQUATIONS
PARTIAL PRESSURE
STEADY-STATE CONDITIONS
SURFACE PROPERTIES
AROMATICS
CHEMICAL REACTIONS
ELEMENTS
EQUATIONS
HYDROCARBONS
KINETICS
METALS
NONMETALS
ORGANIC COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
TRANSITION ELEMENTS
020400* - Petroleum- Processing