Tetrazol-Group Non-Metallocene Catalysts for Olefin Polymerization
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Solution Overview
Problem
Current catalysts for olefin polymerization, particularly non-metallocene systems, face challenges in high temperature stability and efficient production of polyolefins with novel structures, leading to low yield and complex synthesis processes.
Innovation Solution
A transition metal compound with a tetrazol group, represented by Formula 1, is developed, which includes a Group 4 metal such as titanium, zirconium, or hafnium, and is combined with a cocatalyst to form a catalytic composition for efficient olefin polymerization and copolymerization, using a method involving reaction with a strong basic compound like butyl lithium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional non-metallocene catalysts are used for olefin polymerization, then polymerization can proceed, but the catalyst shows low activity and poor stability at high temperatures
Solution Approach 1:
The patent modifies the ligand structure by introducing a tetrazol group with specific substituents (R1-R6) and adjusting electronic parameters through different substituent combinations. This changes the electronic and steric parameters of the catalyst, enabling it to maintain both high activity and stability at elevated temperatures, resolving the contradiction between catalyst stability and polymerization activity
Solution Approach 2:
The catalyst employs a composite ligand system combining tetrazol group with aromatic substituents (such as phenyl, naphthyl, or substituted variants). This composite structure integrates the stability of the tetrazol core with the electronic properties of aromatic groups, achieving both high catalytic activity and thermal stability simultaneously
2Reliability
If complex synthesis processes are used to create novel catalyst structures, then catalyst performance can be improved, but the production process becomes complex and yield decreases
Solution Approach 1:
The ligand is designed as a segmented structure with distinct functional regions: the tetrazol core (providing stability), aromatic substituents (providing electronic control), and specific R-group positions (allowing independent optimization). This segmentation enables systematic optimization of catalyst performance while maintaining a straightforward synthetic route from available precursors
Solution Approach 2:
The patent uses pre-synthesized tetrazol compounds with established aromatic substituents as starting materials. These preliminary prepared compounds with defined structures undergo direct coordination with metal centers, eliminating the need for complex in-situ ligand synthesis and simplifying the overall production process while maintaining high catalyst performance
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 catalytic composition exhibits high activity and stability at high temperatures, enabling the production of polyolefins with high molecular weight and narrow molecular weight distribution, simplifying the production process and increasing yield.
Implementation Method 1
Non-metallocene catalysts having tetrazol group for olefin polymerization
Implementation Method 2
method involving reaction with a strong basic compound like butyl lithium
Data Source
AI summary
The present invention provides a non-metallocene transition metal compound that is easily produced, includes a tetrazol group having the high polymerization activity and high temperature stability in the polymerization of olefins, and a catalytic composition that includes the transition metal compound and a cocatalyst. In addition, the present invention provides a method for efficiently producing an olefin homopolymer or copolymer by using the catalytic composition.