SO/sub 2/-induced isomerization of 2-butene over cation-exchanged X zeolites
Alkali-metal exchanged sodium X zeolites were inactive for cis-2-butane isomerization, but the addition of SO/sub 2/ rendered them active for cis-trans isomerization at a rate that accelerated with time. They remained inactive for double-bond migration. Alkaline-earth exchanged X zeolites were also inactive for cis-2-butene isomerization, but the adsorption of SO/sub 2/ activated them for both geometric and double-bond isomerization, with the ratio of the two initial rates 437:1 for magnesium X, 42.5:1 for calcium X, 23.8:1 for strontium X, and 143:1 for barium X zeolite; the rates increased proportionally to the SO/sub 2/ content for low SO/sub 2/ concentrations. The addition of SO/sub 2/ to rare-earth exchanged X zeolites, which were active for both isomerization types, enhanced the two reactions in a different manner. These results confirmed the previously proposed mechanism of polysulfone-catalyzed geometric isomerization and of double bond migration by a carbonium ion mechanism catalyzed by Broensted acid sites. The variations in activity for geometric isomerization of the various cation-exchanged zeolites correlated well with the cation electrostatic potential or the zeolite electrostatic field.
- Research Organization:
- Tokyo Inst. Technol.
- OSTI ID:
- 6856367
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 56:1; 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)
ALKALI METALS
ALKALINE EARTH METALS
ALKANES
ALKENES
BUTANE
BUTENES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
ELECTROSTATICS
ELEMENTS
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE
ION EXCHANGE MATERIALS
ISOMERIZATION
KINETICS
MATERIALS
METALS
MINERALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE EARTHS
REACTION KINETICS
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
ZEOLITES