|M.Sc Student||Haneen Simaan Yameen|
|Subject||Synthesis of New Catalysts for Polymerization Reaction|
|Department||Department of Chemistry||Supervisor||Full Professor Eisen Moris|
|Full Thesis text|
The purpose of this work was to synthesize homogeneous polymerization catalysts that contain new types of ligands, which can replace cyclopentadiene or its derivatives and understanding its polymerization mechanism process. One of the key advantages of this kind of catalysts over multisite heterogeneous is the well defined active sites, which lead to polymers with specific microstructures and narrow molecular weight distributions. Despite the large number of studies that have been carried out in the field of catalysis for polymerization reactions there is still a need for new catalysts that meet the requirements of the growing demands of new polymers. In this regard, it is important to prepare catalysts that could qualify as outstanding catalysts that are active toward homo and co-polymerization of different α-olefins and provides polymers with varied molecular weight and make the understanding of the polymerization mechanism possible.
In this work, we have studied the syntheses of three different types of ligands which were used to prepare the organometallic complexes, in order to expand our options in finding outstanding catalysts
The first was the imidazolin-2-iminato ligand, which was used for preparing a titanium complex, then study it’s catalytic activity towards the homo polymerization of propylene, ethylene, and 1-hexene and towards the propylene-ethylene co-polymerization, this titanium complex proved to be active in all the above mentioned catalytic reactions.
Using a combination of diverse physical methods such as NMR and EPR and others enabled us to propose a relevant mechanism for the polymerization of propylene, which behaves in a living manner. The effect of using different co-catalysts on the catalytic activity was also studied. Combining these major findings, our catalyst system can consequently be called outstanding.
Concurrently, we synthesized the imidazolin-2-imino-tetramethylcyclopentadiene ligands and their corresponding titanium and zirconium complexes, and studied the effect of different polymerization conditions on the nature of the resulting polypropylene.
The third part of this thesis focused on the synthesis of new chelating NHC (N-Heterocyclic Carbene) ligands derived from the imidazolin-2-iminato ligands and synthesis of respective organometallic complexes.