Ethylene-Methyl Methacrylate Copolymerization Catalyst
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Solution Overview
Problem
The challenge in copolymerization of ethylene and methyl methacrylate is achieving high molecular weight polymers due to the large steric hindrance of methyl methacrylate, leading to poor copolymerization activity and low molecular weight outcomes with existing post-transition metal catalysts.
Innovation Solution
A catalyst system comprising a compound with an a-diimine late-transition metal complex and a bissalicylaldiminato late-transition metal complex in specific mole ratios, along with a co-catalyst, is used to facilitate copolymerization at mild reaction conditions, resulting in high molecular weight ethylene-methyl methacrylate copolymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If post-transition metal catalyst is used for copolymerization of ethylene and methyl methacrylate, then copolymerization can be achieved under low Al oxide to main catalyst ratio (≤1000:1), but the molecular weight of resulting copolymer is low (only 1×10^4 g/mol)
Solution Approach 1:
The patent changes the chemical structure parameters of the catalyst system by introducing a specific ligand framework with electron-donating groups and adjusting the metal center to early transition metals (Ti, Zr, Hf). This parameter change in catalyst structure leads to a parameter change in copolymer molecular weight, increasing it from 1×10^4 to over 1×10^5 g/mol while maintaining copolymerization feasibility.
2Reliability
If methyl methacrylate is used as monomer for copolymerization with ethylene, then functional polyethylene with better compatibility and adhesion can be obtained, but large steric hindrance of methyl methacrylate leads to poor copolymerization activity and low molecular weight
Solution Approach 1:
The patent applies local quality by designing the ligand framework with specific electron-donating groups at particular positions around the metal center. This creates a localized electronic environment that enhances the metal center's ability to activate the monomers, thereby improving copolymerization activity despite the steric hindrance of methyl methacrylate, while preserving the functional benefits of MMA incorporation.
3Reliability
If methyl methacrylate is used as monomer for copolymerization with ethylene, then functional polyethylene with better compatibility and adhesion can be obtained, but large steric hindrance of methyl methacrylate leads to low molecular weight of copolymer
Solution Approach 1:
The patent creates a composite catalyst system combining early transition metal center with specifically designed ligand framework containing electron-donating groups. This composite structure synergistically enhances both the stability needed for high molecular weight copolymer formation and the activity required to overcome the steric hindrance of methyl methacrylate, thereby achieving functional polyethylene with improved properties and higher molecular weight.
4Productivity
If existing copolymerization technology is used, then copolymerization of ethylene and methyl methacrylate can be achieved, but reaction conditions require high temperature and pressure leading to long reaction time
Solution Approach 1:
The patent introduces a specially designed ligand framework as an intermediary between the metal center and the monomers. This ligand acts as a mediator that facilitates monomer activation and insertion at lower temperatures and pressures by providing a favorable electronic and steric environment, thereby improving copolymerization efficiency without requiring harsh reaction conditions.
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
This approach enables the production of ethylene-methyl methacrylate copolymers with molecular weights of at least 1×105 g/mol under low reaction temperatures and pressures, offering high efficiency and adjustable insertion rates of methyl methacrylate.
Implementation Method 1
the coordination copolymerization of ethylene and methyl methacrylate is a technical problem
Implementation Method 2
A catalyst system comprising a compound with an a-diimine late-transition metal complex and a bissalicylaldiminato late-transition metal complex is used to facilitate copolymerization
Data Source
AI summary
The present application provides a catalyst for copolymerization of ethylene and methyl methacrylate and an application thereof. The catalyst includes a main catalyst, and the main catalyst is obtained by compounding a compound of formula (I) and a compound of formula (II); a mole ratio of the compound of formula (I) to the compound of formula (II) is (1:49) to (49:1). The catalyst has an excellent catalytic activity, and a copolymer of ethylene and methyl methacrylate with a high molecular weight can be obtained, with a weight average molecular weight of not less than 1×105 g/mol.