The mechanism of isobutane cracking over amorphous and crystalline aluminosilicates
- Univ. of Pittsburgh, PA (USA)
The acid catalyzed cracking of isobutane over a silica-alumina catalyst and several zeolites was studied. The activity of these catalysts, for whatever reason, increased in the order silica-alumina < H-ZSM-5 < H-Y < H-M, i.e., the same order found in a closely related study of neopentane. The higher the activity the lower was the temperature required to achieve a given conversion, the higher was the paraffin-to-olefin ratios, and the greater was the isomerization of iso- to normal hydrocarbons. It was demonstrated that with all these catalysts two primary reactions occurred resulting in the formation of CH{sub 4} and H{sub 2} and concomitantly the t-butyl and isopropyl cations. The latter either desorbed as the corresponding olefins or underwent secondary reactions. So long as the latter were relatively unimportant the C{sub 3} + C{sub 4} hydrocarbons formed nearly equaled the isobutane reacted. However, the sum of the CH{sub 4} and H{sub 2} produced was generally less than this values. Evidently hydrogen transfer is more important in the conversion of isobutane than of neopentane. This chemistry is discussed.
- OSTI ID:
- 6573487
- Journal Information:
- Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 112:2; ISSN 0021-9517; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020400* -- Petroleum-- Processing
ALKANES
ALKENES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMORPHOUS STATE
CATALYTIC CRACKING
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
CRACKING
CRYSTAL STRUCTURE
DECOMPOSITION
HYDROCARBONS
HYDROGEN PRODUCTION
HYDROGEN TRANSFER
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOMERIZATION
KINETICS
MATERIALS
METHANE
MINERALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
QUANTITY RATIO
REACTION KINETICS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SYNTHESIS
THERMOCHEMICAL PROCESSES
ZEOLITES