Transition Metal Catalyst Ligand Structure for High Molecular Weight Polymers
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Solution Overview
Problem
Current transition metal catalysts fail to produce olefin polymers with ultra-low density and high molecular weight efficiently, and existing catalysts are not easily scalable for commercial applications.
Innovation Solution
A novel transition metal compound with a specific structure, represented by Formula 1, featuring a cyclopentadienyl ligand and an amino group fused to a phenylene bridge, which forms a stable coordination site and allows for controlled bond angles, enabling high activity and copolymerization performance even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional metallocene catalysts are used, then polymerization activity is maintained, but molecular weight decreases at high temperatures and copolymerization degree of alpha-olefin is limited
Solution Approach 1:
The patent modifies the ligand structure parameters by replacing the silicon bridge with a direct bond between the cyclopentadienyl ring and amino group, and by optimizing the substituents on the amino group. This structural parameter change enables the catalyst to maintain high activity while producing high molecular weight polymers at elevated temperatures, resolving the contradiction between productivity and molecular weight.
2Adaptability or versatility
If catalysts with modified bridges (phosphorous, ethylene, propylene, methylidene, or methylene) are used instead of silicon bridge, then structural diversity is increased, but polymerization activity and copolymerization performance deteriorate
Solution Approach 1:
The patent extracts the silicon bridge component from the CGC structure and replaces it with a direct bond between the cyclopentadienyl ring and amino group. This removal of the silicon bridge, combined with optimization of the amino group substituents, maintains the constrained geometry essential for high activity while achieving superior polymerization performance and copolymerization capability.
3Adaptability or versatility
If oxido ligand catalysts are used instead of amido ligand, then ligand variety is increased, but practical application in commercial plants remains limited
Solution Approach 1:
The patent develops a catalyst system with universal applicability by maintaining the amido ligand framework that has proven effective in commercial settings, while introducing systematic variations in substituents to achieve diverse polymer properties. This approach enables both laboratory optimization and commercial scalability, unlike oxido ligand catalysts that remain largely experimental.
4Speed
If high polymerization temperature is applied, then reaction rate is increased, but molecular weight decreases with conventional catalysts
Solution Approach 1:
The patent changes the catalyst structure parameters, specifically the ligand environment around the titanium center, to create a more stable coordination sphere. This structural modification allows the catalyst to maintain high activity at elevated temperatures while preventing premature chain termination, thereby achieving both high reaction rates and high molecular weights simultaneously.
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 novel transition metal compound achieves high molecular weight olefin polymers with ultra-low density, specifically less than 0.910 g/cc, and improved copolymerization properties, making it suitable for various applications including hot melt adhesives and films.
Implementation Method 1
a metal site connected by a cyclopentadienyl (Cp) ligand and an amino group which is fused to a phenylene bridge in a ring shape
Implementation Method 2
a method for preparing a polymer using same
Data Source
AI summary
A transition metal compound having a novel structure is disclosed herein. The transition metal compound can have improved structural stability by forming a stable coordination site of a transition metal through controlling a bond angle formed by the amido group of a phenylene bridge, a cyclopentadienyl ring, and a transition metal. The transition metal compound has excellent copolymerization properties and may produce an olefin polymer having a high molecular weight in a ultra low density region.