Active nature of tellurium-loaded zeolite dehydrocyclization catalysts
The active nature of tellurium-loaded zeolite dehydrocyclization catalysts was examined due to the importance of dehydrocyclization reactions in catalytic reforming to produce high-octane gasolines. Kinetic studies showed that the reactions of cyclohexane and n-hexane over these catalysts to form benzene were both first order in the reactant. The cyclohexane reaction gave Vertical Bar3; 2Vertical Bar3< cyclohexene and cracking products, but the n-hexane reaction also gave n-hexenes and 3-8Vertical Bar3< cracking products. Deuterium tracer tests on cyclohexane and cyclohexene, and kinetic data on the effect of hydrogen concentration on the cyclohexane reaction rate, indicated that the cyclohexane reaction proceeds by a stepwise dehydrogenation. Carbon-14 tracer tests showed that the reaction of n-hexane proceeds only through n-hexenes. Sodium NMR and ESCA spectra indicated that the tellurium is coordinated to the cation associated with the support and that elemental tellurium is the active surface species. A simple dehydrogenation mechanism is proposed involving simultaneous abstraction of two hydrogen atoms by one tellurium atom.
- OSTI ID:
- 6159871
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020400* -- Petroleum-- Processing
ALKANES
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CYCLOALKANES
CYCLOHEXANE
DEHYDROGENATION
ELEMENTS
FUELS
GASOLINE
HEXANE
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOTOPE APPLICATIONS
KINETICS
LIQUID FUELS
MATERIALS
MINERALS
OCTANE
ORGANIC COMPOUNDS
PETROLEUM PRODUCTS
PRODUCTION
REACTION KINETICS
SEMIMETALS
SURFACE PROPERTIES
TELLURIUM
TRACER TECHNIQUES
ZEOLITES