Immobilization of [VCl3(N-2,6-Me2C6H3)] Complex on Silica Supports: Synthesis and Catalytic Testing for Ethylene Polymerization

Abstract

The heterogenization of 2,6-dimethylarylimido-vanadium(V) dichloride via chemical tethering on insoluble silica supports is reported. The effects of the silica particle size, drying conditions, and the reaction time were investigated. The drying conditions of the support were found to be a crucial parameter: drying temperatures over 400 °C were needed to achieve successful catalysis. The supported catalytic systems were characterized by Fourier-transform infrared (FT-IR) spectroscopy, transmission electron microscopy-energy-dispersive X-ray (TEM-EDX), and inductively coupled plasma mass spectroscopy (ICP-MS), while the polymers were characterized by FT-IR, differential scanning calorimetry (DSC), and rheology. Ethylene polymerization tests were performed employing the prepared heterogenized catalysts with methylaluminoxane/diethylaluminum chloride as a cocatalyst. The supported catalyst precursor, when activated with diethylaluminum chloride, promotes the synthesis of polyethylene with seemingly controlled particle size in the absence of reactor fouling, suggesting the successful immobilization of the complex over the inert support. The resulting polymer shows features of ultrahigh-molecular-weight polyethylene (UHMWPE). These findings present a proof-of-concept for a new approach toward the heterogenization of arylimido-vanadium complexes.