Solid Polyaluminoxane Cocatalyst for Olefin Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing solid polyaluminoxane compositions as cocatalysts for olefin polymerization face challenges such as low cocatalytic activity, economic inefficiencies, and difficulties in controlling particle diameter and uniformity, particularly when using solid inorganic carriers like silica, which also affect polymer morphology and stability.
Innovation Solution
A method involving the contact of a polyaluminoxane composition solution with a specific organic compound containing a Group 15-17 element, followed by a reaction under heating conditions, to precipitate a solid polyaluminoxane composition with controlled particle diameter and high recovery rate, eliminating the need for solid inorganic carriers and enhancing cocatalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a polymethylaluminoxane composition solution is added as a cocatalyst in olefin polymerization, then the polymerization reaction proceeds, but it is impossible to control the morphology of the obtainable olefin polymer and stable production is difficult due to fouling problems
Solution Approach 1:
The patent introduces a solid inorganic carrier (silica, alumina, silica-alumina, or magnesium chloride) as an intermediary support for the polymethylaluminoxane composition. This carrier serves as a mediator that enables control over polymer morphology while preventing direct contact between the polymerization system and soluble cocatalyst, thereby reducing fouling issues and improving production stability.
Solution Approach 2:
The patent changes the physical state parameter of the cocatalyst from soluble solution form to solid supported form. By supporting the polymethylaluminoxane composition on solid inorganic carriers with specific particle diameters selected according to the polymerization process type, the patent achieves control over polymer morphology and improves production stability.
2Adaptability or versatility
If a polymethylaluminoxane composition is supported on a solid inorganic carrier, then the carrier particle diameter can be selected to match the polymerization process, but the cocatalytic activity is markedly lower than when used alone
Solution Approach 1:
The patent optimizes the particle diameter parameter of the solid inorganic carrier to match the specific polymerization process requirements (slurry or gas-phase). By carefully selecting carrier particle sizes, the patent maintains adaptability to different processes while minimizing the negative impact on cocatalytic activity through optimized surface area and dispersion.
Solution Approach 2:
The patent creates a composite material system combining the polymethylaluminoxane composition with solid inorganic carriers. This composite structure allows the cocatalyst to benefit from the structural advantages of the carrier (particle diameter control, process compatibility) while maintaining sufficient cocatalytic activity through proper formulation and support methodology.
3Ease of operation
If a polymethylaluminoxane composition is supported on a solid inorganic carrier, then the carrier can be used as a solid cocatalyst, but the carrier tends to remain as foreign matters in polymers and deteriorate polymer properties
Solution Approach 1:
The patent employs solid inorganic carriers that are designed to be consumed or transformed during the polymerization process rather than remaining as permanent foreign matters. The carriers serve their function as solid support for the cocatalyst and are either consumed in the reaction or can be easily separated, reducing their persistence as harmful foreign matters in the final polymer product.
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 resulting solid polyaluminoxane composition exhibits low solubility in solvents, minimizing leaching and fouling, and shows high cocatalytic activity, with controlled particle diameters and uniformity, suitable for existing polymerization processes, and can be produced from commercially available materials with high recovery rates.
Implementation Method 1
Polymethylaluminoxane compositions are produced by the partial hydrolysis reaction of trimethylaluminum
Implementation Method 2
or by the pyrolysis reaction of alkylaluminum compounds which have an aluminum-oxygen-carbon bond formed by the reaction of trimethylaluminum with an oxygen-containing organic compound
Implementation Method 3
a method in which a polyaluminoxane composition in the form of a solution in an aromatic hydrocarbon solvent such as toluene is brought into contact with a bad or poor solvent and thereby a solid polyaluminoxane composition is precipitated
Data Source
AI summary
An object of the invention is to provide a solid polyaluminoxane composition suitably used as a cocatalyst and a catalyst carrier in combination with an olefin oligomerization or polymerization catalyst, without the use of solid inorganic carriers such as silica. The solid polyaluminoxane composition of the invention includes a polyalkylaluminoxane and a trialkylaluminum, and has a solubility in n-hexane at 25° C. of less than 0.50 mol % as measured by a specific method (i), a solubility in toluene at 25° C. of less than 1.0 mol % as measured by a specific method (ii), and a 13 mol % or more molar fraction of alkyl groups derived from the trialkylaluminum moieties relative to the total number of moles of alkyl groups derived from the polyalkylaluminoxane moieties and the alkyl groups derived from the trialkylaluminum moieties as measured with respect to tetrahydrofuran-d8 soluble components by a specific method (iii).