Metallocene Catalyst Structure for Uniform Olefin Copolymerization
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Solution Overview
Problem
Existing metallocene catalysts lack a novel structure and efficient preparation methods, limiting their performance in olefin polymerization.
Innovation Solution
A metallocene compound with a novel structure represented by Chemical Formula 1, prepared by reacting a metallocene catalyst precursor with an organic lithium compound and a Group 4 transition metal compound, and optionally supported on carriers like silica or silica-alumina, with a cocatalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional metallocene catalysts are used, then the polymerization process is simple, but the molecular weight distribution is broad and comonomer distribution is non-uniform
Solution Approach 1:
The catalyst ligand is divided into two separate cyclopentadienyl rings with different substituent patterns, where each ring provides specific functional groups (R1-R5 substituents) that independently control different aspects of polymerization, enabling precise control over molecular weight distribution and comonomer incorporation
Solution Approach 2:
Different regions of the metallocene catalyst structure are assigned different properties: one cyclopentadienyl ring has substituents R1-R3 that control steric environment, while the other ring has substituents R4-R5 that control electronic properties, creating local quality differences that achieve uniform comonomer distribution and narrow molecular weight distribution
2Productivity
If novel metallocene structures are developed, then copolymerization activity increases, but the preparation method becomes more complex
Solution Approach 1:
The metallocene precursor compound is prepared in advance with pre-installed substituents R1-R5 in specific positions on the cyclopentadienyl rings, and the desired stereochemistry is established before the final metal coordination step, simplifying the overall synthesis of high-activity copolymerization catalysts
Solution Approach 2:
A metallocene precursor compound with specific ligand structure serves as an intermediary that facilitates the introduction of controlled substituents R1-R5 on cyclopentadienyl rings, enabling systematic variation of catalyst properties while maintaining a standardized preparation pathway that enhances copolymerization 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 metallocene compound exhibits improved performance in olefin polymerization, offering narrow molecular weight distribution and uniform comonomer distribution, enhancing copolymerization activity.
Implementation Method 1
a step of adding an organic lithium compound to the metallocene catalyst precursor to prepare a lithium salt
Implementation Method 2
a step of allowing the lithium salt to react with a Group 4 transition metal compound
Implementation Method 3
Metallocene catalysts are compounds in which a ligand such as a cyclopentadienyl group, an indenyl group, or a cycloheptadienyl group is coordinately bonded to a transition metal or transition metal halide compound, and they are used as catalysts for olefin polymerization
Data Source
Figure 1
AI summary
The metallocene compound of the present disclosure is represented by the following Chemical Formula 1: (Z, R1, R2, R3, R4, R5, n, m, p, q, X1, X2, Q1, and Q2 are as defined in the specification.)