Synthesis and Evaluation of New Bis(imino) Pyridine Based Catalysts for Ethylene Polymerization

Abstract

Abstract. Three-component catalytic systems based on 2,6-bis(imino) pyridine iron(II) chloride were synthesized from different ligands, which provided new alternative catalysts for polymerization of ethylene. The synthesized catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), and the lack of absorption bands was observed in the region related to the carbonyl, as well as the presence of bands in the region of imino groups corresponding to C=N bonds. Coordination with Fe was also carried out. The structure of the ligands and the new catalysts were confirmed by the elemental analysis (CHN), and 1 H-and 13 C-nuclear magnetic resonance spectroscopy. In ethylene polymerization with methylaluminoxane as a cocatalyst, the activity of catalyst C1 was high. Although this catalyst structure contains sterically bulky ligands, the metal center was not sufficiently protected allowing transfer reactions, producing polyethylene with a low molar mass and melting temperature.

Evaluation of Bis(imino)pyridine Iron Catalyst on Heterogeneous Ethylene Polymerization

“…Supported systems generated catalytic activities lower than their analogous homogeneous catalysts. It can also be mentioned that, analogously to the homogeneous catalysts, the supported systems C1 and C2 obtained greater performance than the C4 catalyst [14].…”

“…Homogeneous solutions of different bis(imino) pyridine iron complexes in toluene were prepared and 0.005 mmol Fe was directly employed in the ethylene polymerization reactions [14]. All polymerization reactions were performed in a 1 l Büchi glass reactor equipped with a mechanical stirrer, connected to a thermostatic system.…”