This paper describes the preparation of some active organometallic species derived from nickel, titanium and zirconium fixed on the surface of different supports and their behaviour for the catalytic polymerization of ethylene. In the case of nickel, the transition metal species were attached to cro
Acetylene polymerization on supported transition metal clusters
✍ Scribed by Ken Judai; Stéphane Abbet; Anke S Wörz; Anna Maria Ferrari; Livia Giordano; Gianfranco Pacchioni; Ueli Heiz
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 460 KB
- Volume
- 199
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
The polymerization of acetylene, studied experimentally and theoretically on nanocatalysts consisting of nanoscale clusters of different size and elemental composition, is reviewed. As on bulk systems palladium is the most active transition metal for this reaction. More important, however, is the changing selectivity as function of size and elemental composition. As an example, palladium atoms, dimers, and trimers, as well as nanoscale copper clusters are highly selective for the cyclotrimerization reaction. In the case of palladium, the -bonding of acetylene and a charge transfer from the substrate to the atom/cluster are responsible for the high selectivity. In addition DFT calculations revealed the whole reaction path of this reaction on palladium atoms and it could be shown that in contrast to bulk systems the rate-determining step is the formation of benzene from the Pd(C 4 H 4 )C 2 H 2 complex.
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The autooxidation of cumene to cumene hydroperoxide (CHP) in the presence of a supported catalyst was invesugartid. When Cu(OAc), was supported on Chelex, polyvinylpyridine or Si@, it was demonstrated that polyvinylpyridine and SiOl are poor supports for a catalyst in cumene autooxidation. Several m
## Abstract Summary: Facile and effective immobilization of late‐transition metal catalysts, 2,3‐bis‐(2,6‐diisopropylphenyl)butane diimine nickel(ii) dibromide (A) and 2,6‐bis‐[1‐(2,4,6‐trimethylphenylimino)ethyl]pyridine iron(ii) dichloride (B), for ethylene polymerization has been achieved, using