Synthesis and catalytic studies of Ti-anchored disilanol isobutyl-POSS/alkylaluminum system

Titanium (IV) precursors anchored to alkyl substituted polyhedral oligomeric silsesquioxane (POSS) disilanol were prepared and characterized. These catalysts formulated as [Ti(O^O)2] and [M(O^O)XCl] are found to be active in polymerization of ethylene at high temperatures in combination with ethylaluminum sesquichloride (Et3Al2Cl3) as co-catalyst. The polyethylene product so obtained is linear, crystalline and displays narrow dispersities. The unique low molecular weight PE formed in this reaction exhibit properties that have potential industrial applications. The effect of various reaction parameters on catalyst performance is described.

Homogeneous complexes of titanium supported on a substituted polyhedral oligomeric silsesquioxane (POSS) disilanol formulated as [(POSS-(O^O))2Ti 1 and POSS-(O^O)MCl 2–5] were synthesized. These supported catalysts were found to be active for the polymerization of ethylene at high temperature and pressure. Low molecular weight PE with narrow dispersities were obtained in presence of ethylaluminum sesquichloride (Et3Al2Cl3) as co-catalyst.Figure optionsDownload high-quality image (117 K)Download as PowerPoint slideHighlights
► Titanium supported POSS catalysts are active for ethylene polymerization.
► Low molecular weight polyethylene formation at high temperature and pressure.
► Alkylaluminumhalide co-catalyst plays a key role in molecular weight regulation.
► Effect of substituents on metallocenes affect catalyst productivity.