Mechanism of dimethylbutene isomerization over alumina
Extensive experimental results showed that 3,3-dimethyl-1-butene exchanges deuterium from D/sub 2/, deuterated ethylene, or deuterated propylene on alumina only with vinylic hydrogen; that the skeletal isomerization of 3,3-dimethyl-1-butene, which proceeds via a carbonium ion mechanism, is not poisoned by H/sub 2/S, which is known to poison isomerization via m-allylic species and which can thus be used as a probe for mechanistic studies; and that double-bond migration of 2,3-dimethyl-2-butene occurred on alumina activated at 948/sup 0/K without forming m-allylic intermediates and an alumina activated at 723/sup 0/K to approx. 83Vertical Bar3< via m-allylic species, which suggested that in cases where tertiary carbonium ions can be formed by protonation of the alkene, the Broensted acid character of alumina is sufficient to produce them at 300/sup 0/K and that they contribute to the isomerization. Various other aspects of deuterium exchange and isomerization are discussed.
- Research Organization:
- Univ. of Edinburgh
- OSTI ID:
- 6811210
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 57:2; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BUTENES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ACTIVATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DEUTERIUM
HYDROCARBONS
HYDROGEN ISOTOPES
ISOMERIZATION
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
STABLE ISOTOPES
TEMPERATURE EFFECTS