Non-bridged Arylphenoxy Catalyst for High-Temperature Ethylene Polymerization

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Solution Overview

Problem

Conventional catalyst systems for producing ethylene homopolymers or copolymers of ethylene and α-olefins face challenges such as wide molecular weight distribution, non-uniform compositional distribution, and reduced activity at high temperatures, particularly in solution polymerization processes.

Innovation Solution

A non-bridged arylphenoxy-based transition metal catalyst system with cyclopentadienyl derivatives and arylphenoxide ligands as fixed ligands around a group 4 transition metal, which are not crosslinked, and used in combination with aluminoxane or boron compounds as cocatalysts, enabling high molecular weight production at elevated temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If metallocene catalyst system is used, then molecular weight distribution becomes narrow and compositional distribution becomes uniform, but molecular weight becomes limited and polymerization activity reduces at high temperatures

Engineering Contradiction:

Improvemolecular weight distribution and compositional distribution uniformityVSAvoidpolymerization activity at high temperatures

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the chemical structure parameters of the catalyst by using non-metallocene cyclopentadienyl ligands with specific substituent patterns (R1-R8 groups) and arylphenoxy ligands with ortho-substitution, creating a unique steric and electronic environment around the group 4 transition metal that enables high activity at elevated temperatures while maintaining controlled polymerization

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The catalyst system combines multiple components: a group 4 transition metal center, non-metallocene cyclopentadienyl ligands with specific substitution patterns, arylphenoxy ligands with ortho-substitution, and aluminoxane cocatalysts. This composite structure achieves synergistic effects that resolve the contradiction between uniformity and high-temperature activity

Inventive Principle:

Principle #40Composite materials

2Productivity

If solution polymerization process is conducted at high temperatures, then process efficiency improves, but polymerization activity is rapidly reduced and beta-hydrogen elimination becomes dominant

Engineering Contradiction:

Improveprocess efficiencyVSAvoidpolymerization activity stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The catalyst structure is designed in advance with specific ligand configurations (non-metallocene cyclopentadienyl with R1-R8 substituents and arylphenoxy with ortho-substitution) that prevent beta-hydrogen elimination reactions before they can occur, allowing the catalyst to maintain stability and activity at high solution polymerization temperatures

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent modifies the chemical parameters of the catalyst system by introducing specific ligand structures with controlled steric bulk and electronic properties, changing the reaction pathway parameters to favor polymerization over beta-hydrogen elimination even at elevated temperatures

Inventive Principle:

Principle #35Parameter changes

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 catalyst system achieves high catalytic activity and thermal stability, allowing for the production of ethylene homopolymers or copolymers with varied physical properties at high temperatures, surpassing conventional metallocene and non-metallocene catalysts in terms of molecular weight and process efficiency.

Implementation Method 1

Arylphenoxy-based transition metal catalyst system with cyclopentadienyl derivatives and arylphenoxide ligands as fixed ligands around a group 4 transition metal

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

non-bridged arylphenoxy-based transition metal catalyst system with cyclopentadienyl derivatives and arylphenoxide ligands as fixed ligands around a group 4 transition metal

Methodology Applied

Scientific EffectCoordination chemistry:

Data Source

PatentUS7589042B2Arylphenoxy catalyst system for producing ethylene homopolymer or copolymers of ethylene and alpha-olefins

Publication Date: 2009.09.15 SABIC NEXLENE CO PTE LTD

AI summary

Disclosed is an arylphenoxy catalyst system for producing an ethylene homopolymer or copolymers of ethylene and α-olefins, and a method of producing an ethylene homopolymer or copolymers of ethylene and α-olefins having a high molecular weight under a high temperature solution polymerization condition using the same. The catalyst system includes a group 4 arylphenoxy-based transition metal catalyst and an aluminoxane cocatalyst or a boron compound cocatalyst. In the transition metal catalyst, a cyclopentadienyl derivative and arylphenoxide as fixed ligands are located around the group 4 transition metal, arylphenoxide is substituted with at least one aryl derivative and is located at the ortho position thereof, and the ligands are not crosslinked to each other. The catalyst includes non-toxic raw materials, synthesis of the catalyst is economical, and thermal stability of the catalyst is excellent. It is useful for producing an ethylene homopolymer or copolymers of ethylene and α-olefins having various physical properties in commercial polymerization processes.