1,3-Butadiene hydrogenation on single crystals of platinum. I. Mechanism and carbon deactivation of Pt(110)

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

DOI:https://doi.org/10.1016/0021-9517(87)90307-1· OSTI ID:5204471

Oudar, J; Pinol, S; Berthier, Y

1,3-Butadiene hydrogenation and H/sub 2/-D/sub 2/ exchange have been simultaneously investigated on the Pt(110) surface at 200-400 Torr pressure. The surface was characterized by Auger electron spectroscopy (AES) and LEED before and after the reaction. Depending on the hydrogen pressure, two kinetic regimes were observed. First, at high hydrogen pressure (above 130 Torr), the order of the reaction is one with respect to hydrogen and zero with respect to butadiene. The selectivity does not depend on the hydrogen pressure. The surface is covered by one butadiene molecule for every two surface atoms of platinum. As revealed by LEED analysis after reaction, the butadiene monolayer shows no structural order. Moreover, AES measurement performed at grazing incidence gives evidence for the adsorption of the butadiene molecules in the valleys of the unreconstructed (110) face. Second, below a critical hydrogen pressure (approx. 125 Torr), the order of the reaction is two with respect to hydrogen and zero with respect to butadiene. The selectivity toward butane decreases as the hydrogen pressure decreases. The carbon concentration is higher than that in the previous case. The lower-temperature carbon deactivation seems to result from the selective poisoning of the hydrogen dissociation sites by some hydrocarbon species. A reaction mechanism is proposed according to which the rate-determining step is the hydrogenation of the half-hydrogenated product C/sub 4/H/sub 7/.

• Research Organization: Universite Pierre et Marie Curie, Paris (France)
• OSTI ID: 5204471
• Journal Information: J. Catal.; (United States), Vol. 107:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
BUTADIENE
HYDROGENATION
CATALYSTS
DEACTIVATION
PLATINUM
CATALYTIC EFFECTS
AUGER ELECTRON SPECTROSCOPY
CARBON
CHEMICAL REACTION KINETICS
DEPOSITION
DEUTERIUM
HYDROGEN
ISOTOPIC EXCHANGE
LAYERS
LOW PRESSURE
PETROLEUM
POISONING
REFINING
SURFACE PROPERTIES
CHEMICAL REACTIONS
DIENES
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
METALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PLATINUM METALS
POLYENES
PROCESSING
REACTION KINETICS
SPECTROSCOPY
STABLE ISOTOPES
TRANSITION ELEMENTS
020400* - Petroleum- Processing