Transition Metal Complex Catalyst for Olefin Polymerization
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Solution Overview
Problem
Metallocene catalysts for olefin polymerization face challenges such as sensitivity to impurities, high costs due to the need for alumoxanes, difficulties in supporting catalysts, and synthetic complexity, especially when aiming for tactic polymerization of propylene.
Innovation Solution
A transition metal complex with a specific skeletal unit, optionally combined with an activator, is used for polymerizing unsaturated monomers like ethylene or propylene, or copolymerizing ethylene with higher olefins, featuring a delocalized unsaturated ring system and a divalent bridging group for improved activity and comonomer incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metallocene catalysts are used for olefin polymerization, then high activity is achieved, but sensitivity to impurities increases
Solution Approach 1:
The patent introduces a specific ligand system as an intermediary between the metal center and the monomer. This ligand acts as a protective intermediary that filters out impurities while maintaining catalytic activity, allowing the catalyst to operate reliably with commercially available monomers without requiring excessive purification
2Productivity
If metallocene catalysts are used to achieve high activity, then large quantities of expensive alumoxanes are required
Solution Approach 1:
The patent extracts and eliminates the need for alumoxane by designing a catalyst system that achieves high activity through the metal-organic compound and ligand combination alone. This removes the harmful dependency on expensive activators while maintaining productivity
Solution Approach 2:
The patent replaces expensive, quantity-intensive alumoxane with a small amount of carefully designed ligand that provides sustained catalytic activity. The ligand acts as a more efficient, long-lasting alternative that reduces overall material consumption
3Productivity
If metallocene catalysts are used for polymerization, then high activity is achieved, but difficulties in putting catalyst on support arise
Solution Approach 1:
The patent segments the catalyst system into a metal-organic compound component and a separate ligand component. This segmentation allows independent optimization of each component and facilitates easier support attachment, as the ligand can be attached to supports before metal coordination occurs
4Productivity
If metallocene catalysts are used for propylene polymerization, then activity is achieved, but synthetic difficulties in producing complex catalyst structures occur
Solution Approach 1:
The patent inverts the conventional approach by first establishing the metal-organic compound and then adding the ligand in a separate step. This inverted sequence simplifies synthesis, as the ligand can be introduced after the metal framework is established, reducing overall synthetic complexity while maintaining catalytic functionality
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 solution provides high activity in polymerizing and copolymerizing olefins with enhanced comonomer incorporation, reducing the need for expensive activators and improving catalyst stability and efficiency.
Implementation Method 1
transition metal-based polymerisation catalysts and to their use in the polymerisation and copolymerisation of olefins
Implementation Method 2
catalyst compound comprising the skeletal unit... wherein M is a group 3 to 11 transition metal
Data Source
AI summary
A complex compound comprising the skeletal unit of Formula A,wherein the ring represented by C(R1)-A1-A2-(A3)x-C(R2)—C— has delocalised unsaturation and is optionally substituted via one or more of A1, A2 and A3 with atoms or groups selected from hydrogen, alkyl, aryl, halogen, or heterocyclic groups containing at least one N, S or O in a carbon ring; A1, A2 and A3 are selected from carbon, nitrogen or oxygen, R1 and R2 are each selected from chlorine, bromine or iodine; x is zero or 1, O is oxygen, E is nitrogen, phosphorus or arsenic, Q represents a divalent bridging group comprising one or more Group 14 atoms; M is a metal selected from Groups 3 to 7; X represents a monovalent atom or group covalently or ionically bonded to M; L is a mono- or bidentate molecule datively bound to M, y satisfies the valency of M and z is from 0 to 5. The complex can be used to polymerise olefins optionally with organo-A1 or -B compounds as activator.