Polyfunctional Activator Precursors for Metallocene Catalyst Efficiency
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Solution Overview
Problem
Silica-supported methylaluminoxane catalysts have low efficiency due to the need for a large excess of methylaluminoxane and limited support capacity, resulting in inefficient activation of metallocene molecules.
Innovation Solution
Development of novel activator precursor compositions comprising a support material in contact with a linking compound and a polyfunctional compound with aromatic groups having polar monoprotic groups, forming stable and highly active catalyst systems under inert conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silica-supported methylaluminoxane is used as metallocene catalyst activator, then the catalyst system can activate metallocene molecules, but the efficiency is low due to the need for large excess of methylaluminoxane and limited support capacity
Solution Approach 1:
The patent modifies the chemical structure of methylaluminoxane by introducing aromatic groups with polar monoprotic groups (such as phenolic hydroxyl groups) at controlled distances from the aluminum center. This structural parameter change enables the aluminoxane to effectively activate metallocene at lower Al:Zr ratios (greater than 50:1), significantly reducing the quantity of aluminoxane required while maintaining high catalytic efficiency
Solution Approach 2:
The patent creates a composite activator system comprising modified aluminoxane molecules with integrated aromatic groups containing polar monoprotic groups. These composite structures combine the activating capability of aluminoxane with the stabilizing and directing effects of aromatic polar groups, achieving high efficiency at reduced aluminoxane concentrations
2Productivity
If a large excess of methylaluminoxane is used to effectively activate metallocene molecules, then activation efficiency improves, but the cost and complexity of the system increases
Solution Approach 1:
By changing the molecular parameters of aluminoxane through the introduction of aromatic groups with polar monoprotic groups at specific distances from the aluminum center, the patent achieves effective metallocene activation at much lower Al:Zr ratios (greater than 50:1) compared to conventional systems. This parameter modification reduces both the quantity of aluminoxane needed and the associated system complexity
3Ease of manufacture
If standard grades of silica are used as support, then the support material is readily available, but the amount of methylaluminoxane that can be supported is limited
Solution Approach 1:
The patent modifies the aluminoxane molecule itself rather than the silica support, introducing aromatic groups with polar monoprotic groups that enable more effective utilization of the supported aluminoxane. This approach maintains compatibility with standard silica supports while achieving higher effective aluminoxane capacity through molecular design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The new compositions exhibit higher efficiency and stability, significantly improving the activation of metallocenes and enhancing the polymerization process by forming highly active catalyst systems.
Implementation Method 1
a support material in contact with a linking compound
Implementation Method 2
When a methylaluminoxane is reacted with a metallocene, a metallocene-dialkylaluminum cation forms
Data Source
AI summary
This invention provides activator precursor compositions and activator compositions. The activator precursor compositions are formed from a support material, a linking compound, and polyfunctional compounds having at least two aromatic groups in which at least two of said aromatic groups each has at least one polar moiety thereon. The activator compositions are formed from a support material, a linking compound, an aluminoxane, and a polyfunctional compound having at least two aromatic groups in which at least two of said aromatic groups each has at least one polar moiety thereon. Also provided are catalyst compositions, processes for forming catalyst compositions, and polymerization processes utilizing the catalyst compositions of this invention.