Aluminoxane-based Activator Chemistry

塑料是一种用途广泛的材料，用于各种各样的产品。聚烯烃是一类由烯烃单体（含有C=C双键的简单分子）聚合形成长链烃（以C-C单键为主）而制成的塑料。在催化剂的帮助下，它们在世界范围内大量生产。催化剂在不影响自身的情况下加速化学反应，在制备聚烯烃时，使用含有过渡金属的催化剂。然而，催化剂在能够协助所需的转化之前需要活化，而这一活化步骤的关键工业方法是使用大量过量的高活性化合物甲基铝氧烷（MAO）。过量的使用是如此之高（1000-10,000当量），以至于MAO占催化系统成本的很大一部分。过量使用可能是由于MAO的激活成分仅占整体的一小部分，但MAO的复杂性使得它在超过25年的时间里一直没有明确的表征。

Plastics are versatile materials used in an enormous array of products. Polyolefins are one class of plastics made from polymerizing olefin monomers (simple molecules containing a C=C double bond) to form a long chain hydrocarbon (with a backbone of C-C single bonds). They are made in huge quantity worldwide with the help of catalysts. Catalysts speed chemical reactions without themselves being affected, and in the preparation of polyolefins, catalysts containing transition metals are used. However, the catalyst requires activation before it is able to assist the desired transformation, and the key industrial approach to this activation step is to use a large excess of a highly reactive compound called methylaluminoxane (MAO). The excess used is so high (1000-10,000 equivalents) that MAO represents a significant proportion of the cost of the catalytic system. The excess used is probably due to the fact that the activating component(s) of MAO are present only as a small fraction of the whole, but the complexity of MAO is such that it has resisted unambiguous characterization for over 25 years. We plan to use electrospray ionization mass spectrometry (ESI-MS), a tool most often applied to the study of biological macromolecules, to the problem of MAO characterization. Our preliminary results demonstrate the feasibility of our approach, we have identified a likely candidate for the active ingredient of MAO, and we are well set to demonstrate its relevance in an industrially relevant setting. Promising compounds will be targeted synthetically, and we will use the experience and resources of our supporting organization, NOVA Chemicals, to explore the activity of the new materials that we discover. Our goal is ultimately learn enough about aluminoxane chemistry to greatly reduce the required excess of this material in catalyst activation, substantially reducing the cost of this step in forming polyolefin materials: this chemistry will become cleaner, safer and less expensive, and the significance of such a discovery is high due to the vast quantities of polyolefins prepared every year.