Phenylene-Bridged Transition Metal Catalyst for Low-Density Polyolefin
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Solution Overview
Problem
Conventional transition metal catalysts with silicon bridges and oxido ligands exhibit low activity and poor copolymerization performance for ethylene and alpha-olefin polymerization, limiting their industrial application.
Innovation Solution
A novel transition metal complex with a phenylene bridge and specific ligand structures, such as those represented by Formulas 1, 2, and 3, is developed, which allows for stable pentagon ring formation and improved steric and electronic environments for monomer coordination, enhancing polymerization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional transition metal catalysts with silicon bridges and oxido ligands are used, then the catalyst structure is stable, but the polymerization activity is low and copolymerization performance is poor
Solution Approach 1:
The patent changes the bridge structure from silicon to phenylene, and modifies the ligand structure from oxido to amido/alcoxy groups, thereby changing the chemical and physical parameters of the catalyst to achieve both high activity and good copolymerization performance
Solution Approach 2:
The patent creates a composite catalyst system combining phenylene bridge with specific amido or alcoxy ligands coordinated to transition metals, forming a new composite structure that exhibits synergistic effects for improved polymerization performance
2Speed
If high polymerization temperature is used, then the reaction rate increases, but the catalyst activity decreases for conventional catalysts
Solution Approach 1:
The phenylene bridge structure provides dynamic flexibility that allows the catalyst to maintain stability at high temperatures while remaining active, adapting the catalyst structure to withstand thermal conditions without deactivation
3Adaptability or versatility
If alpha-olefin with large steric hindrance is used, then the copolymerization capability is improved, but the polymerization activity decreases for conventional catalysts
Solution Approach 1:
The patent creates a local environment around the metal center with specific steric and electronic properties through the phenylene bridge and amido/alcoxy ligands, allowing selective accommodation of bulky alpha-olefins while maintaining high catalytic activity
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 catalyst composition achieves high molecular weight polyolefin copolymers with low density and high copolymerization activity, even at high temperatures, and allows for the incorporation of a great amount of alpha-olefin, resulting in polymers with densities less than 0.910 g/cc.
Implementation Method 1
transition metal complex containing a phenylene bridge, a method of synthesizing the same, and olefin polymerization using the transition metal complex
Data Source
AI summary
Provided are a novel transition metal complex where a monocyclopentadienyl ligand to which an amido or alcoxy group is introduced is coordinated, a method of synthesizing the same, and olefin polymerization using the transition metal complex. Compared to a conventional transition metal complex having a silicon bridge and an oxido ligand, the transition metal complex has a phenylene bridge, so that a monomer easily approaches the transition metal complex in terms of structure and a pentagon ring structure of the transition metal complex is stably maintained. The catalyst composition including the transition metal complex is used to synthesize a polyolefin copolymer having a very low density less than 0.910 g/cc.