A magnesium chloride supported bis(cyclopentadienyl)-zirconium(IV) dichloride catalyst for the polymerization of ethylene

Abstract

SUMMARY: A magnesium chloride supported zirconocene catalyst was synthesized using a soluble tetrahydrofuran complex of magnesium chloride. The supported catalyst polymerizes ethylene with high activities in the presence of methylaluminoxane. The siginificant feature of the supported catalyst is that it polymerizes ethylene even at temperature as high as 100 8C at low Al/Zr ratios. The polymer molecular weights obtained using supported catalyst are found to be higher compared to the unsupported catalyst. The molecular weight distribution index is in the range of 2.0 -2.5. The active site concentration of the supported catalyst was found to be five times lower than that of the unsupported catalyst.

“Bound but Not Gagged”Immobilizing Single-Site α-Olefin Polymerization Catalysts

“…The polyethylene molecular weight distribution was significantly narrower than that obtained using silica alone. A related preparation not involving the use of silica involved the addition of a THF solution of MgCl 2 and metallocene to excess hexane to precipitate a solid catalyst . Another example of the use of THF in catalyst immobilization using MgCl 2 involves treatment of MgCl 2 (THF) 2 with an aluminum alkyl and subsequently Cp 2 ZrCl 2 .…”

Cationic Pyridylamido Adsorbate on Brønsted Acidic Sulfated Zirconia: A Molecular Supported Organohafnium Catalyst for Olefin Homo- and Co-Polymerization

“…Unlike homogeneous Cat1 (entries 1, 2, 8, 9), the supported catalyst shows moderate activity for both ethylene homopolymerization and ethylene/1-octene copolymerization, even in the absence of an exogenous cocatalyst/activator. However, the activity of the supported organo-Hf catalyst is lower, possibly reflecting catalyst–support steric crowding, slower monomer diffusion into the supported catalyst interior pores, or a lower fraction of active centers. ,,− Nevertheless, it remains active for multiple hours to produce significant quantities of polymer at higher ethylene pressure (entries 5 and 6, Table ). The molecular mass of the polyethylene product is also much greater than that of the homogeneous Hf system (1674 vs 181 kg mol –1 , entries 3 vs 1, Table ).…”

Ethylene Polymerization with Silica‐Supported Nickel‐Diimine Catalyst: Effect of Support and Polymerization Conditions on Catalyst Activity and Polymer Properties

“…[9][10][11][12] Metallocene catalysts can be effectively supported on different types of inorganic carriers, the most frequently used are spherical silica, MgCl 2 and Al 2 O 3 . [10][11][12][13][14][15][16][17][18][19] Metallocene catalysts have also been supported on polymeric carriers such as polystyrene particles. [17] Spherical silica is one of the most commonly used catalyst carriers, since it leads to good polymer particle morphology.…”