Lanthanide Oxo-Nitrogenated Complex for High Cis-Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current catalytic systems for the polymerization of conjugated dienes, particularly those using lanthanides, face challenges in achieving high 1,4-cis units content in polybutadiene and polyisoprene while avoiding metal residues and radioactive by-products, which limits their industrial application for producing high-quality rubber.
Innovation Solution
Development of an oxo-nitrogenated complex of lanthanides with a specific formula, combined with aluminum alkyls and aluminoxanes, to create a catalytic system that achieves a high content of 1,4-cis units in polybutadiene and polyisoprene, exceeding 99% for polybutadiene and 98% for polyisoprene, with improved processability and molecular weight distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalytic systems comprising lanthanides (such as cerium, neodymium, praseodymium, or gadolinium) are used for the polymerization of conjugated dienes, then the content of 1,4-cis units in the resulting polybutadiene can reach about 98%, but metal residues remain in the polymer which cause oxidation of the polymer
Solution Approach 1:
The invention changes the chemical composition parameters of the catalytic system by introducing a specific oxo-nitrogenated ligand structure with particular steric and electronic properties. This modifies the lanthanide center's coordination environment to achieve high stereoselectivity while reducing metal residue harmful effects through optimized catalyst deactivation pathways
Solution Approach 2:
The oxo-nitrogenated ligand acts as an intermediary between the lanthanide metal center and the diene substrate. The specific ligand structure mediates the polymerization process to achieve high 1,4-cis selectivity while its design allows for controlled metal residue formation that is less oxidizing to the polymer
2Manufacturing precision
If catalytic systems comprising uranium allyls are used to provide polybutadiene with very high content of 1,4-cis units (≥ 99%), then the stereospecificity is improved, but radioactive residues remain in the polymers obtained
Solution Approach 1:
The invention replaces expensive and hazardous uranium-based catalysts with lanthanide-based catalysts that are cheaper, non-radioactive, and environmentally friendly. The lanthanide catalyst achieves comparable or superior stereosspecificity without the harmful radioactive residues, effectively substituting a harmful short-living solution with a safe sustainable one
Solution Approach 2:
The invention changes the metal center parameter from radioactive uranium to non-radioactive lanthanides (Ce, Nd, Pr, Gd), fundamentally altering the catalyst's safety profile while maintaining or improving its stereoselectivity for producing high 1,4-cis polybutadiene
3Productivity
If catalytic systems comprising titanium, cobalt, or nickel are used for polymerization, then the process can be conducted, but the content of 1,4-cis units is limited and cannot reach the very high levels achieved by lanthanide or uranium systems
Solution Approach 1:
The invention changes the metal center parameter to lanthanides with specific ionic radii and coordination geometries that are optimal for achieving high 1,4-cis selectivity. The oxo-nitrogenated ligand further tunes the electronic and steric parameters of the catalyst to maximize stereospecificity while maintaining high polymerization activity
Solution Approach 2:
The invention creates a composite catalytic system combining lanthanide metal center with specifically designed oxo-nitrogenated ligand framework. This composite structure synergistically combines the high activity of lanthanide metals with the stereodirecting capabilities of the nitrogenous ligand, achieving both high productivity and high 1,4-cis content
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 system effectively produces polymers with exceptionally high 1,4-cis units content, matching the properties of natural rubber, with improved resistance to aging and reduced polydispersity, making them suitable for industrial rubber production.
Implementation Method 1
catalytic system comprising said oxo-nitrogenated complex of lanthanides for the (co)polymerization of conjugated dienes
Data Source
Figure 1
Figure 2(a)~2(f)
Figure 3
AI summary
A bis-imine pyridine complex of lanthanides having general formula (I). Said bis-imine pyridine complex of lanthanides having general formula (I) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.