Isotope studies of the isomerization of olefins homogeneously catalysed by palladium, platinum, and rhodium complexes
No entry of deuterium into olefin could be detected as a result of isomerization of allylbenzene in the presence of palladium(II) -catalysts in CH/ sub 3/CO/sub 2/D or CH/sub 3/OD. The deuterium isotope effect o n the rate of isomerization was found to be high in the case of CH/sub 3/CO/sub 2/D, but slight in the case of CH/sub 3/OD. In the case of ca talysis by rhodium complexes, entry of deuterium into olefin occurs in CH/sub 3/OD but not in CH/sub 3/CO/sub 2/ D. Isotope effects parallel those obser ved with palladium(II). The isomerization of PhCD/sub 2/CH/sub 2/CH = CH/sub 2/ cata lysed by palladium(II) results in a near-to-random distribution of deuterium throughout the side chain. The results are consistent with a hydrido- pi -olefin complex mechanism of isomerization. Differences between catalysis by palladium(II) and rhodium(III) are discussed in terms of possible differences in the mechanism of formation of the active catalyst. In the case of palladium it is concluded that a relatively rapid rate of sigma - pi interchange and hence of double bond shift occurs within the equilibrium system of catalyst and olefin, and that exchange of olefin with the substrate constitutes the slower, rate-determining step. The behavior of platinum(II) is generally similar to that of palladium(II) but is only effective at higher temperatures. (auth)
- Research Organization:
- Univ. of New South Wales, Kensington, Australia
- NSA Number:
- NSA-29-002471
- OSTI ID:
- 4425271
- Journal Information:
- Aust. J. Chem., v. 26, no. 9, pp. 1935-1947, Other Information: Orig. Receipt Date: 30-JUN-74; Bib. Info. Source: AUS (Australia (sent to DOE from))
- Country of Publication:
- Australia
- Language:
- English
Similar Records
Advances in hydroformylation catalysis
Ruthenium, rhodium, and iridium complexes of thiophene and benzo(b)thiophienes: Models for catalytic hydrodesulfurization
Related Subjects
Organic
& Physical Chemistry-Isotopic Effects
*DEUTERIUM- ISOTOPE EFFECTS
ACETIC ACID
ALKENES
AROMATICS
CATALYSIS
CATALYSTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DEUTERIUM COMPOUNDS
ISOTOPIC EXCHANGE
METHANOL
PALLADIUM COMPLEXES
PLATINUM COMPLEXES
RHODIUM COMPLEXES