(608b) Silica Tethered Sulfonic Acids for Activation of Olefin Polymerization Catalysts
AIChE Annual Meeting
2006
2006 Annual Meeting
Catalysis and Reaction Engineering Division
Polymerization Reaction Engineering, Kinetics and Catalysis II
Thursday, November 16, 2006 - 3:36pm to 3:57pm
A variety of co-catalysts have been developed to activate metallocenes for the polymerization of olefins including methylaluminoxane (MAO), boranes, borates and sulfated metal oxides. MAO or borane based co-catalysts are most commonly used as activators for polymerization of olefins. However, these technologies represent relatively expensive co-catalysts. Basic raw material cost calculations show that co-catalysts such as MAO can represent over 60% of the cost of typical polymerization recipes. Thus, alternative, low cost replacements for these co-catalysts are continuously being sought. For the first time, the utilization of an organic/inorganic hybrid material is reported as a co-catalyst for borane and MAO-free metallocene activation for olefin polymerizations. Silica tethered sulfonic acids combined with small amounts of trimethylaluminum (TMA) or triisobutylaluminum (TIBA) act as activators for either Cp*2ZrCl2 or Cp*2ZrMe2 in the polymerization of ethylene. Various control experiments indicate that the in-situ formation of the known co-catalyst MAO is not likely the mechanism of activation. Similar to sulfated metal oxides (SMOs), the catalytic activation step most likely occurs via metal-carbon protonolysis. This is a new, potentially low cost activator/support for single-site olefin polymerization.