Isotopic exchange of cyclic ethers with deuterium over metal catalysts. [Using Pt and Rh catalysts]

Journal Article · Thu Jul 01 04:00:00 EDT 1976 · J. Catal.; (United States)

OSTI ID:7239045

Duchet, J C; Cornet, D

The exchange reaction between deuterium and cyclic ethers (oxolane and ..cap alpha..-methyl derivatives) has been investigated using rhodium and palladium catalysts. The first hydrogen undergoing exchange has been found to be located on a ..beta..-carbon. This fact, and the poisoning of the exchange of cyclopentane in the presence of ether, suggest that the O atom participates in the exchange mechanism of ethers. It appears, however, that the oxygen--metal bonding occurs only during this simple exchange process; simultaneous adsorption of oxygen and a vicinal carbon causes hydrogenolysis of the O--C bond. In each case multiple exchange is important. In the oxolane molecule two sets of exchangeable hydrogens are distinguished according to their reactivities, as could be expected by analogy with cycloalkanes. However, this distinction is not so clear in the exchange patterns of substituted oxolanes, since intermediate maxima are observed in these cases. It is suggested that the conformational properties of the substituted rings cause a constraint in the formation of 3,4-diadsorbed oxolanes. Thus, multiple exchange, based on ..cap alpha..,..beta..-process, and epimerization via the ''roll-over'' mechanism occur preferentially in certain parts of the molecules.

• Research Organization: Universite de Caen, France
• OSTI ID: 7239045
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 44:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400303* -- Organic Chemistry-- Isotope Exchange & Isotope Separation-- (-1987)
CATALYTIC EFFECTS
DEUTERIUM
ELEMENTS
ETHERS
HYDROGEN ISOTOPES
ISOTOPES
ISOTOPIC EXCHANGE
LIGHT NUCLEI
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
REFRACTORY METALS
RHODIUM
STABLE ISOTOPES
TRANSITION ELEMENTS