Język
en
Treść
Vanadium catalyst systems (SIL1–3A(B)/V) for ethylene polymerization were obtained by immobilization of the Cp2VCl2precursor (V) in the ionic liquid -[3-(triethoxysilyl)propyl]pyridinium chloride (IL), modified by AlCl3 and AlEtCl2(A) or AlEt2Cl (B), and supported on three types of silica carrier S1–3. The properties of the ionic liquid supports were determined using Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller measurements, scanning electron microscopy and elemental analysis. The best results (above 2 tons PE (mol V)−1(0.5 h)−1) were obtained using the catalyst system SIL3B/V. Addition of ethyl trichloroacetate is possible in the ionic liquid medium and it further increases the activity up to 7 tons PE(mol V)−1(0.5 h)−1. In contrast, application of the imidazolium ionic liquid to the SIL system or application the analogous catalystsystem without the ionic liquid results in lower activities. The obtained polyethylene (PE) is a linear polymer, with molecular weight (Mw)ofover106gmol−1and molecular weight distribution (Mw/Mn) in the range 1.6–1.9, and has a characteristic fluffy or fibrous shape. In contrast, the PE samples obtained using the systems without ionic liquid reveal broader Mw/Mn(2.5–3.7)and replicate the support morphology.
