Catalysis and surface chemistry. II. Reactions of propylene over reduced molybdena-alumina catalysts

Conference · Tue Jul 01 04:00:00 EDT 1980 · J. Catal.; (United States)

OSTI ID:6898249

Lombardo, E A; Jacono, M L; Hall, W K

When cyclopropane was isomerized using a microcatalytic pulse technique over a reduced molybdena-..gamma..-alumina catalyst (0.3 to 1.5 e/Mo), the resulting propene underwent secondary reactions including polymerization, metathesis to ethene and butenes, and hydrogenation (in H/sub 2/ carrying gas) to propane, ethane, and butane. Isotope exchange also occurred when D/sub 2/ or cyclopropane-d/sub 6/ was used. Complementary tracer studies were also made with propene-d/sub 0/ and D/sub 2/ using a static recirculation system. The kinds of sites required for the several reactions were classified and estimates made of their concentrations using strongly adsorbed (poison) molecules as probes. Small amounts of CO and NO were effective poisons for hydrogenation and exchange, but not for isomerization or metathesis in these experiments, but some poisoning of isomerization by CO was observed in pulse experiments. H/sub 2/O, pyridine, and NH/sub 3/ were less selective, but all of the reactions tested were poisoned. CO/sub 2/ and N/sub 2/O were ineffective and O/sub 2/ appeared to selectively reoxidize the active hydrogenation sites. From the data obtained, it could be estimated that the site concentrations utilized for these reactions were much lower than the measurable parameters such as anion vacancies, Mo/sup 4 +/ or Mo/sup 5 +/ centers, etc.; they amounted to no more than a few percent of the Mo present and may have corresponded to multiplet vacancies. The chemisorption of NO and of CO correlated with both the extent of reduction and the vacancy concentration as did hydrogenation and exchange, and these same molecules, when chemisorbed, effectively poisoned these reactions.

• Research Organization: Univ. of Wisconsin, Milwaukee
• OSTI ID: 6898249
• Conference Information: Journal Name: J. Catal.; (United States) Journal Volume: 64:1
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010403* -- Coal & Coal Products-- Hydrogenation-- (-1987)
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10 SYNTHETIC FUELS
ALKANES
ALKENES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMMONIA
AZINES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
CYCLOALKANES
DEUTERIUM
HETEROCYCLIC COMPOUNDS
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROGENATION
ISOMERIZATION
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN HYDRIDES
NITROGEN OXIDES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POISONING
POLYMERIZATION
PROPYLENE
PYRIDINES
REDUCTION
SEPARATION PROCESSES
SORPTION
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS
WATER