Nickel Palladium Catalysts for Ethylene Acrylate Copolymerization
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Solution Overview
Problem
Existing catalyst systems for ethylene and acrylate polymerization are incompatible with acrylates, leading to blocked active sites and hindered polymerization, and often result in slow rates of polymerization and low acrylate incorporation.
Innovation Solution
Development of a ligand framework for Ni and Pd catalysts that promotes high rates of ethylene copolymerization and high incorporation of acrylate comonomers, using a procatalyst structure that includes a nickel(II) or Pd(II) metal center with specific ligands to facilitate linear copolymer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Group IV metal catalysts (Ti, Zr, Hf) are used for ethylene polymerization, then high productivity and linear polyethylene structure are achieved, but the catalyst becomes incompatible with acrylate comonomers due to strong coordination of oxygen atoms blocking the active site
Solution Approach 1:
The patent changes the metal center from Group IV (Ti, Zr, Hf) to Group 10 (Ni, Pd), fundamentally altering the electronic and steric parameters of the catalyst. This parameter change allows the catalyst to accommodate both ethylene and acrylate comonomers without site blocking, achieving versatility while maintaining productivity through the specific ligand framework design
Solution Approach 2:
The patent introduces a specific ligand framework as an intermediary component that mediates between the metal center and the monomers. This ligand framework prevents direct coordination between acrylate oxygen atoms and the metal center, while still allowing ethylene insertion, thus enabling compatibility with both monomer types
2Adaptability or versatility
If electron-rich metal catalysts containing Group 10 metals (Pd, Ni) are used to address acrylate compatibility, then acrylate incorporation is improved, but the rates of polymerization become slow and acrylate incorporation remains low
Solution Approach 1:
The patent optimizes the electronic and steric parameters of the Ni or Pd catalyst by selecting specific ligands from defined classes (formula I ligands with specific R groups and functional groups). This parameter optimization enhances both acrylate compatibility and polymerization rate simultaneously, resolving the contradiction between adaptability and productivity
Solution Approach 2:
The patent applies local quality by designing ligands with specific functional groups (Y groups in formula I) that provide localized electronic effects at the metal center. These local electronic modifications create optimal conditions for both acrylate coordination and ethylene insertion, achieving high productivity with maintained versatility
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 new catalyst systems achieve high rates of ethylene copolymerization and significant acrylate incorporation, resulting in highly linear ethylene/acrylate copolymers with improved creep resistance and dimensional stability at elevated temperatures.
Implementation Method 1
Coordination catalysis provides routes to highly linear ethylene/acrylate copolymers with structures similar to that of linear low-density polyethylene (LLDPE)
Implementation Method 2
Y is a Lewis base. Optionally, Y and X in formula (I) are covalently connected
Data Source
AI summary
Processes of polymerizing olefin monomers using catalyst systems and catalysts systems that include a procatalyst having a structure according to formula (I).