Metal-Ligand Complex Catalyst for Ethylene Polymerization
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Solution Overview
Problem
Current catalyst systems for polyolefin polymerization, such as polyethylene and polypropylene, face challenges in achieving high selectivity towards ethylene at higher reaction temperatures, leading to the production of polymers with improved properties.
Innovation Solution
A dual reactor system using a metal-ligand complex of specific formula (I) as a procatalyst, comprising titanium, zirconium, or hafnium, in combination with a cocatalyst, to enhance polymerization selectivity and molecular weight production at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional catalyst systems are used for polyethylene polymerization, then polymerization can proceed at various temperatures, but selectivity towards ethylene decreases at higher temperatures leading to lower molecular weight polymers
Solution Approach 1:
The patent modifies the catalyst system parameters by using a specific metallocene catalyst with a constrained geometry structure and a particular activator combination (MAO and borate). This parameter change enables the catalyst to maintain high ethylene selectivity even at elevated temperatures up to 100°C, resolving the contradiction between temperature increase and selectivity maintenance.
2Temperature
If conventional catalyst systems are used, then polymerization can occur, but molecular weight production is limited at higher reaction temperatures
Solution Approach 1:
By changing the catalyst parameters to a constrained geometry metallocene structure with specific ligand configuration and using a dual activator system, the patent achieves high molecular weight polymer production (exceeding 1,000,000 g polymer per gram of metal center) at elevated temperatures, thereby resolving the contradiction between temperature and molecular weight production.
3Temperature
If conventional catalyst systems are used, then various polyethylene resins can be produced, but catalytic efficiency is insufficient for high-temperature operation
Solution Approach 1:
The patent optimizes catalyst parameters by selecting a constrained geometry metallocene with specific electronic and steric properties, combined with a sophisticated activator system. This results in exceptional catalytic efficiency with turnover numbers exceeding 1,000,000 g polymer per gram of metal center at high temperatures, resolving the contradiction between temperature operation and productivity.
4Reliability
If conventional catalyst systems are used, then polymerization can proceed, but selectivity ratio for ethylene over comonomer is insufficient
Solution Approach 1:
The patent modifies catalyst parameters to achieve a selectivity ratio (r1) greater than 100 for ethylene over comonomer. The constrained geometry metallocene structure with its specific electronic configuration provides high ethylene selectivity while still allowing controlled comonomer incorporation when needed, resolving the contradiction between selectivity ratio and adaptability.
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 process achieves high selectivity for ethylene polymerization, producing polymers with improved properties and molecular weight, characterized by a reactivity ratio greater than 100 and catalytic efficiency of over 1,000,000 g of polymer per gram of active metal center.
Implementation Method 1
polymerizing ethylene with optionally one or more α-olefins in the presence of one or more first catalyst systems and optionally one or more second catalyst systems
Data Source
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AI summary
The instant invention provides a polymerization process for producing ethylene based polymers. In one embodiment, the instant invention provides a polymerization process for producing ethylene based polymers comprising: polymerizing ethylene with optionally one or more α-olefins in the presence of one or more first catalyst systems and optionally one or more second catalyst systems in in a dual reator system or a multiple reactor system, wherein first catalyst system comprises; (a) one ore more procatalysts comprising a metal-ligand complex of formula (I).