Helmut Alt

Laboratorium für Anorganische Chemie, Universität Bayreuth, Postfach 101251, D-95440 Bayreuth, Germany

[ 1 ] - The effect of iodo substituents in bis(phenoxyimine) zirconium complexes on the catalytic performance of homogeneous ethylene polymerization reactions

Eight different zirconium phenoxyimine complexes were synthesized, characterized and tested as catalysts for ethylene polymerization. The phenoxyimine compounds were prepared by condensation of substituted salicylaldehydes with aliphatic and aromatic amines, the substituted salicylaldehydes from ortho substituted phenols and paraformaldehyde. The introduction of iodo substituents was achieved e...

[ 2 ] - Intelligent catalysts for ethylene oligomerization and polymerization

EEthylene polymerization catalysts became available in an enormous variety. The challenge in this research is to find catalysts that are able to connect ethylene molecules in such a way that not only linear chains are produced but variations like branched materials that possess very interesting mechanical properties like linear low density polyethylene (LLDPE). In this contribution, three diffe...

[ 3 ] - Dissymmetric dinuclear transition metal complexes as dual site catalysts for the polymerization of ethylene

A series of dissymmetric dinuclear complexes were synthesized, as dual site catalysts in ethylene polymerization, by coupling the allylated a-diimine complexes of the metals Ti, Zr, V, Ni and Pd with the ansa-zirconocene complex [C5H4-SiH(Me)-C5H4]ZrCl2 possessing a hydride silane moiety. The different stages of syntheses included the formation of bis(cyclopentadienide)methyl silane which was u...

[ 4 ] - Homogeneous and heterogeneous oligomerization reactions of olefins with unbridged metallocene catalysts

1-Pentene, respectively 1-hexene, were reacted with 13 homogeneous metallocene catalysts to give linear oligomerization products, predominantly dimers, with selectivities above 90%. The product distributions of the codimerization reactions of 1-pentene with 1-hexene reflected a binomial behaviour. Therefore, the ratio for dimers is 1:2:1 (C10:C11:C12) while the trimers (pentadecenes up to octad...

[ 5 ] - Halogen substituted iron(III) di(imino)pyridine complexes as catalysts for 1- pentene/1-hexene co-oligomerization reactions

Nine different bis(arylimino)pyridine complexes of Fe(III) with different halide substituents (F, Cl, Br, I) at different positions of the iminophenyl group of the ligand have been synthesized, characterized and applied for homogeneous 1-pentene and 1-hexene oligomerization and co-oligomerization reactions after activation with methylaluminoxane (MAO). The best activity in 1-hexene oligomerizat...

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