Crosslinked Bisindenyl Ligand for High-Temperature Olefin Polymerization
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Solution Overview
Problem
Current catalysts for olefin polymerization, particularly those derived from constrained-geometry catalysts, face challenges in maintaining high activity and copolymerization performance at high temperatures and with large steric hindrance olefins, with few being applicable in commercial factories.
Innovation Solution
A novel ligand compound and transition metal compound with a specific crosslinked bisindenyl structure, combined with indoline or tetrahydroquinoline groups, are developed to enhance catalyst stability and activity, allowing for the synthesis of high molecular weight polyolefins, particularly isotactic polypropylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metallocene catalysts are used for olefin polymerization, then basic catalytic function is achieved, but catalytic activity and copolymerization performance deteriorate at high temperatures and with large steric hindrance olefins
Solution Approach 1:
The patent modifies the ligand structure by introducing a crosslinked bisindenyl structure combined with indoline or tetrahydroquinoline groups, changing the steric and electronic parameters of the catalyst to maintain high activity and stability at elevated temperatures
Solution Approach 2:
The patent creates a composite ligand system combining bisindenyl groups with indoline/tetrahydroquinoline moieties, integrating multiple functional elements into a single catalyst structure that simultaneously provides thermal stability and high catalytic activity
2Adaptability or versatility
If conventional metallocene catalysts are used, then simple structure is maintained, but copolymerization performance with large steric hindrance olefins deteriorates
Solution Approach 1:
The patent introduces specific functional groups (indoline or tetrahydroquinoline) at particular positions of the bisindenyl ligand structure, creating local electronic and steric environments that enhance copolymerization ability with large steric hindrance olefins like 1-hexene and 1-octene
Solution Approach 2:
The crosslinked bisindenyl structure with substituted indoline or tetrahydroquinoline groups creates an asymmetric coordination environment around the metal center, improving copolymerization performance by better accommodating different olefin substrates
3Productivity
If chloride groups in metallocene are substituted with other ligands, then catalytic activity may increase, but catalyst complexity and synthesis difficulty increase
Solution Approach 1:
The patent pre-synthesizes the complex crosslinked bisindenyl ligand with indoline/tetrahydroquinoline groups before metal coordination, allowing the sophisticated ligand structure to be prepared and characterized separately, then combined with the metal center in a final straightforward step
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 system demonstrates high catalytic activity and stability at elevated temperatures, producing polymers with improved isotacticity and molecular weight, outperforming existing catalysts in both homopolymerization and copolymerization of olefins.
Implementation Method 1
The novel catalyst system demonstrates high catalytic activity and stability at elevated temperatures, producing polymers with improved isotacticity and molecular weight
Data Source
AI summary
The present invention relates to a novel ligand compound, a preparation method thereof, a transition metal compound including the ligand compound, and a preparation method thereof. The ligand compound of novel structure according to the present invention and the transition metal compound including the same may be used as a polymerization reaction catalyst for preparing olefin polymers.