Stereoselective thymol hydrogenation. I. Kinetics of thymol hydrogenation on charcoal-supported platinum catalysts
- Institut de Recherches sur la Catalyse-CNRS, Villeurbanne (France)
The kinetics of thymol hydrogenation on a well-characterized supported platinum catalyst have been investigated in cyclohexane at temperatures between 313 and 373 K and under 3 MPa of hydrogen pressure. The relative rate constants of the different reaction pathways (hydrogenation via menthone or isomenthone, and direct hydrogenation to the four menthol diastereoisomers) were determined from the changes in composition of the reaction medium during the reaction process. It has been shown that hydrogenation via the menthone intermediates is the major route, the formation of the cis isomer (isomenthone) being favored. The configuration of the menthols, produced from direct hydrogenation or from the ketone intermediates, is controlled by the geometry of adsorption of the precursors on the metal surface, so that neoisomenthol with all substituents in the cis position is by far the most abundant steroisomer produced. 21 refs., 11 figs., 2 tabs.
- OSTI ID:
- 6201385
- Journal Information:
- Journal of Catalysis; (United States), Vol. 140:1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PLATINUM COMPOUNDS
CATALYTIC EFFECTS
THYMOL
HYDROGENATION
ADSORPTION
CATALYST SUPPORTS
CATALYSTS
CHARCOAL
CHEMICAL REACTION KINETICS
CONFIGURATION
GEOMETRY
HETEROGENEOUS CATALYSIS
HYDROGEN
KETONES
REACTION INTERMEDIATES
STEREOCHEMISTRY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
ADSORBENTS
AROMATICS
CATALYSIS
CHEMICAL REACTIONS
ELEMENTS
HYDROXY COMPOUNDS
KINETICS
MATHEMATICS
NONMETALS
ORGANIC COMPOUNDS
PHENOLS
REACTION KINETICS
SORPTION
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties