Catalytic reactions of hydrocarbons over Pt-Pd alloys--3. Skeletal reactions of n-pentane and n-hexane over Pt-Pd/Sio/sub 2/ catalysts
The isomerization, cyclization, and hydrogenolysis kinetics of n-pentane and n-hexane were studied on dispersed silica-supported 1% alloy consisting of 0-100% palladium/platinum. The catalysts were calcined for 25 hr at 600/sup 0/C prior to reduction or only reduced in hydrogen at 400/sup 0/C. The surface composition was probably similar to bulk composition. The catalytic activity vs. composition curves were similar for precalcined and uncalcined catalysts and for various reaction temperatures (300/sup 0/-360/sup 0/C). For n-pentane, hydrogenolysis was higher on palladium than on platinum or low-palladium alloys but more selective towards butane on platinum; isomerization decreased with increasing palladium content; and cyclization went through a maximum on alloy catalysts. The reaction patterns were similar with n-hexane, except that precalcination of the catalyst suppressed cyclization to methylcyclopentane and benzene. The catalysts underwent a poisoning process which was generally highest at the higher temperatures and higher palladium contents. The results were compared with results obtained on Pt-Pd foil and mechanisms were discussed.
- Research Organization:
- Institute Physical Chemical, Polish Academy Science
- OSTI ID:
- 6456489
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 63:2; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKANES
ALLOYS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
DEHYDROCYCLIZATION
HEXANE
HYDROCARBONS
ISOMERIZATION
KINETICS
ORGANIC COMPOUNDS
PALLADIUM ALLOYS
PENTANE
PLATINUM ALLOYS
PLATINUM METAL ALLOYS
POISONING
REACTION KINETICS
TEMPERATURE EFFECTS