Amino-Imine Metal Complex for High-Temperature Ethylene Polymerization
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Solution Overview
Problem
Existing polyethylene catalysts, such as α-diimine nickel catalysts, suffer from reduced activity and molecular weight decrease at elevated temperatures, making them unsuitable for industrial applications requiring high-temperature polymerization.
Innovation Solution
Development of an amino-imine metal complex with specific structural components, including R1-R12 groups and metal M, which provides thermal stability and allows for high-temperature catalytic polymerization of ethylene to produce branched polyethylene with high molecular weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If α-diimine nickel catalysts are used for ethylene polymerization at high temperature, then polymerization speed increases, but catalyst activity decreases rapidly and molecular weight decreases
Solution Approach 1:
The patent modifies the ligand structure from α-diimine to amino-imine type, changing the chemical parameters of the catalyst system. This structural parameter change enables the catalyst to maintain high activity at elevated temperatures (60-90°C) where conventional α-diimine catalysts would lose activity, thus resolving the contradiction between temperature and catalyst reliability
Solution Approach 2:
The invention creates a composite catalyst system combining amino-imine ligand with nickel metal center and aluminum alkyl cocatalyst. This composite structure synergistically enhances thermal stability while maintaining catalytic activity, allowing the system to operate effectively at higher temperatures without the activity loss seen in conventional catalysts
2Productivity
If polymerization temperature is increased, then reaction efficiency improves, but molecular weight of polyethylene decreases rapidly
Solution Approach 1:
By changing the catalyst structure from α-diimine to amino-imine type, the patent modifies the reaction parameters to enable high-temperature polymerization while maintaining high molecular weight. The amino-imine ligand structure creates a more stable metal center that suppresses chain transfer reactions even at elevated temperatures, thus preserving molecular weight while improving productivity
Solution Approach 2:
The patent achieves dynamic control over the polymerization process by using an aluminum alkyl cocatalyst system that can adapt to temperature changes. The cocatalyst dynamically adjusts the active species concentration and reactivity, allowing the system to maintain optimal performance across a range of temperatures without sacrificing molecular weight
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 amino-imine metal complex maintains catalytic activity and produces polyethylene with high molecular weight even at elevated temperatures, addressing the limitations of existing catalysts and enhancing industrial suitability.
Implementation Method 1
The amino-imine metal complex maintains catalytic activity and produces polyethylene with high molecular weight even at elevated temperatures
Data Source
AI summary
An amino-imine metal complex represented by Formula I, its preparation method and an application thereof are provided. The complex is used as a main catalyst in catalysts for olefin polymerization, and can catalyze the polymerization of ethylene at a relatively high temperature to prepare branched polyethylene having high molecular weight.