Bis-Phenyl-Phenoxy Metal-Ligand Complexes for Selective Olefin Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing catalyst systems for olefin polymerization, such as those used in producing polyethylene and polypropylene, struggle to achieve high molecular weights with a narrow molecular weight distribution and high selectivity towards ethylene, particularly at elevated temperatures.
Innovation Solution
Development of a catalyst system comprising a metal-ligand complex with a lanthanide or scandium metal center, featuring specific ligands and oxidation states, designed to enhance catalyst efficiency and selectivity during ethylene and α-olefin copolymerization reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalyst systems are used for olefin polymerization, then polymer production is achieved, but the molecular weight distribution is broad and selectivity towards ethylene is insufficient
Solution Approach 1:
The patent changes the fundamental parameters of the catalyst system by using Group III or Lanthanide metals with specific oxidation states (+3 or +4) and coordinating them with tailored ligands (TnX2-n where T is an aromatic hydrocarbon and X is a hydrocarbyl or heterohydrocarbyl group). This parameter change in metal identity, oxidation state, and ligand structure enables narrow molecular weight distribution while maintaining high catalyst efficiency and ethylene selectivity
Solution Approach 2:
The invention creates a composite catalyst system by combining the metal center (Group III or Lanthanide) with a specifically designed ligand framework. The ligand system comprises aromatic hydrocarbon groups with hydrocarbyl substituents, forming a composite structure that synergistically provides both the structural framework for narrow molecular weight distribution and the active sites for high productivity
2Productivity
If polymerization is conducted at elevated temperatures, then reaction rate increases, but selectivity towards ethylene and molecular weight control deteriorate
Solution Approach 1:
The patent employs parameter changes by selecting metals with higher oxidation states (+3 or +4) that possess greater thermal stability and maintain their catalytic activity and selectivity at elevated temperatures. The specific ligand architecture with aromatic hydrocarbon groups provides thermal stability while the metal center maintains high ethylene selectivity even at high reaction temperatures, enabling both high productivity and manufacturing precision
3Strength
If high molecular weight polymers are produced, then polymer quality improves, but catalyst efficiency and reaction selectivity decrease
Solution Approach 1:
The invention applies parameter changes by using Lanthanide metals or Group III metals in +3 or +4 oxidation states, which enable the production of high molecular weight polymers through enhanced chain growth capability. The specific ligand system with aromatic hydrocarbon groups and hydrocarbyl substituents stabilizes the high molecular weight chains while maintaining high catalyst efficiency, resolving the traditional trade-off between polymer strength and productivity
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 catalyst system achieves high selectivity and efficiency in producing polymers with varying molecular weights at elevated temperatures, addressing the limitations of existing systems by improving molecular weight distribution and selectivity.
Implementation Method 1
catalyst system comprising a metal-ligand complex according to formula (I)... M is scandium, yttrium, a lanthanide metal or an actinide metal having an oxidation state of +3... produce polymers with a high or low molecular weight at high temperature
Data Source
AI summary
Embodiments of this disclosure are directed to catalyst systems comprising a metal-ligand complex according to formula (I).