Competitive hydrogenation of butadiene and butene on palladium and platinum catalysts

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

DOI:https://doi.org/10.1016/0021-9517(89)90180-2· OSTI ID:7086437

Ouchaib, T

In a recent study of the selective hydrogenation of butadiene to butenes, the reactivity of palladium (in the form of single crystals and of supported catalysts) was compared with that of platinum. The reactivity of single-crystal faces with (111) orientation is comparable to that of SiO{sub 2}-supported catalysts. The argument put forward to explain the comparatively lower activity of platinum was its lower hydrogen coverage under a given pressure, in the presence of the hydrocarbons, arising from a heat of adsorption smaller than that on palladium (respectively 67 and 85 kJ/mol). Concerning its poorer selectivity toward butenes, the reason invoked was a similar heat of adsorption for butadiene and butenes: the olefinic intermediate compound remains partly on the surface and the reaction proceeds to butane. A powerful kinetic method which is able to provide direct evidence for this different adsorption of dienes and butenes would be the competitive hydrogenation of these two molecules. However, to distinguish between the ethylenic hydrocarbon formed during the reaction and the molecules already present in the reactants, the experiments were performed according to the sequence: competitive hydrogenation of a butadiene-propene mixture followed by the hydrogenation of a 1-butene-propene mixture. This paper describes a study which confirms that the reason for the selectivity of palladium (after stabilization of the catalyst) can be attributed unambiguously to its capacity of adsorbing a diene more strongly than an alkene molecule.

• OSTI ID: 7086437
• Journal Information: Journal of Catalysis; (USA), Vol. 119:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
BUTADIENE
HYDROGENATION
BUTENES
PALLADIUM
CATALYTIC EFFECTS
SORPTIVE PROPERTIES
PLATINUM
ADSORPTION
ADSORPTION HEAT
ALKENES
CHEMICAL REACTION KINETICS
COMPARATIVE EVALUATIONS
COMPETITION
CRYSTAL STRUCTURE
KINETIC EQUATIONS
MIXTURES
PROPYLENE
CHEMICAL REACTIONS
DIENES
DISPERSIONS
ELEMENTS
ENTHALPY
EQUATIONS
HYDROCARBONS
KINETICS
METALS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
POLYENES
REACTION KINETICS
SORPTION
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
020400* - Petroleum- Processing