Abstract
M.Sc.
Polymerization of a-olefins by metallocene-based catalysts, is an ever expanding field
with current scientific research continuing in an endeavor to develop chiral catalysts
with greater stereospecificity and activities. However, the application of metallocene
catalysts in oligomerization reactions of a-olefins has been somewhat neglected. This
is despite the fact that metallocene catalysis can offer a convenient route to the
synthesis of higher a-olefin oligomers. Furthermore, by utilizing an assortment of
functional group transformations, a-olefin oligomers can serve as intermediates for a
variety of specialty chemicals. Notwithstanding the possibility of employing
alternative ligands in catalysis, the use of non-cyclopentadienyl-based complexes is a
topic that has only recently been considered.
Comparative studies of a series of analogous complexes is lacking in this field and
thus a pertinent study of a number of known metallocene complexes was executed in
this project. Furthermore, an industrially applicable process for oligomerization was
sought after. This was in fact achieved by subjecting the a-olefins 1-pentene, 1-
hexene and 1-octene, to oligomerization conditions with a previously unreported and
lowered methylaluminoxane ratio. This reaction proved to be highly selective to dimer
formation of the three aforementioned higher a-olefins. In order to gain more insight
into the oligomerization process, the progress of the reaction was also followed. Only
zirconium complexes were synthesized and furthermore, the induction of
oligomerization as opposed to polymerization (using compounds known to be active
solely as polymerization catalysts), was attempted by increasing the reaction
temperature.
The second part of this project entailed the synthesis and subsequent testing of
zirconium catalysts containing non-cyclopenatadienyl-based ligands. These
complexes have frameworks with chelating phenolate or naphtholate ligands. These
complexes were tested for oligomerization, but results proved to be negative.