Penta-coordinate Bis-phenylphenoxy Catalysts for Ethylene Polymerization
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Solution Overview
Problem
Current methods for producing low molecular weight, semi-crystalline ethylene-based polymers require significantly low polymerization temperatures, limiting reactor throughput and efficiency.
Innovation Solution
Development of molecular transition metal complexes, specifically penta-coordinate metal complexes with a single atom bridge structure, which enable the formation of low molecular weight ethylene-based polymers at elevated temperatures, enhancing catalyst activity and reactor throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional catalyst systems are used to produce low molecular weight ethylene-based polymers, then the polymerization temperature must be significantly low, but this limits reactor throughput and efficiency
Solution Approach 1:
The patent changes the chemical structure parameters of the catalyst system by introducing a specific bis-phenylphenoxy ligand framework with adjustable substituents (R groups) and a single-atom bridge (Y). This structural modification enables the catalyst to function at elevated temperatures while maintaining activity for producing low molecular weight polymers, thus resolving the contradiction between temperature and productivity
2Quantity of substance
If conventional bis-phenylphenoxy catalysts are used, then low molecular weight polymers can be produced, but significantly low polymerization temperatures are required
Solution Approach 1:
The patent creates a composite catalyst structure combining the metal center (M) with a specifically designed bis-phenylphenoxy ligand system featuring a single-atom bridge. This composite structure integrates the properties of the metal complex with the stabilized ligand framework, enabling control over polymer molecular weight while operating at higher temperatures than conventional catalysts
3Productivity
If the catalyst structure is modified to enable higher temperature operation, then reactor throughput improves, but catalyst complexity increases
Solution Approach 1:
The patent segments the catalyst structure into distinct functional components: the metal center (M), the bis-phenylphenoxy ligand framework, the single-atom bridge (Y), and variable substituents (R groups). This segmentation allows systematic optimization of each component's contribution to catalyst performance, enabling high-temperature operation while maintaining reasonable structural complexity through modular 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 use of these complexes allows for the production of low molecular weight, semi-crystalline ethylene-based polymers at higher temperatures, improving catalyst efficiency and reactor productivity, making them suitable for applications like hot melt adhesives.
Implementation Method 1
The invention provides a molecular transition metal complex and a process to form an ethylene-based polymer... polymerizing a mixture comprising ethylene, and optionally at least one comonomer, in the presence of at least one molecular transition metal complex
Data Source
Figure 1
AI summary
The invention provides a molecular transition metal complex selected from Formula 1, as described herein; an ethylene-based polymer; and a process to form the ethylene-based polymer, said process comprising polymerizing ethylene in the presence of at least one molecular transition metal complex selected from Formula 1, as described herein, and wherein either Z1 or Z2 is dative covalent (coordinate) to the metal (M).