Phosphorus Phenolate Metal Complex for High-MW α-Olefin Copolymerization
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Solution Overview
Problem
Existing catalysts are ineffective for copolymerizing α-olefins with polar group-containing monomers, leading to low polymerization activity and molecular weight, particularly in the production of α-olefin polymers and copolymers.
Innovation Solution
A novel transition metal complex with a phosphorus phenolate ligand structure is developed, enabling homopolymerization of α-olefins and copolymerization with polar group-containing monomers, resulting in higher molecular weight polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional metallocene catalysts are used, then polymerization activity is maintained, but catalyst half-life is short due to decomposition
Solution Approach 1:
A bulky N-heterocyclic carbene ligand acts as an intermediary protective group around the zirconium center, shielding it from decomposing agents while allowing olefin substrate access. This steric protection mechanism extends catalyst half-life by preventing decomposition pathways without sacrificing polymerization activity.
2Productivity
If catalyst activity is increased, then productivity improves, but catalyst stability decreases leading to faster decomposition
Solution Approach 1:
The patent modifies the ligand parameters by introducing specific bulky groups (such as mesityl, 2,6-diisopropylphenyl) at defined positions around the carbene center. These parameter changes create an optimal balance where the steric bulk is sufficient to protect the catalyst from decomposition but not so large as to block substrate access, thereby maintaining high activity while extending half-life.
3Reliability
If steric bulk of ligand is increased to protect catalyst, then catalyst stability improves, but accessibility of active site decreases
Solution Approach 1:
The ligand design implements local quality by placing bulky protective groups at specific peripheral positions (ortho positions of the N-heterocyclic ring) while keeping the central carbene carbon and coordination site accessible. This localized steric protection allows the catalyst to maintain high activity at the active site while being protected overall, resolving the contradiction between stability and accessibility.
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 achieves higher polymerization activity, allowing the production of α-olefin homopolymers and copolymers with increased molecular weight.
Implementation Method 1
a catalyst for olefin polymerization which comprises a metal complex of formula (1) [zirconium complex with N-heterocyclic carbene ligand]
Data Source
Figure 1
AI summary
Provided are a novel catalyst component with excellent polymerization activity, for producing an α-olefin polymer and an α-olefin copolymer, especially a polymer having a high molecular weight, and a method for producing an α-olefin polymer and an α-olefin copolymer using the catalyst component. A metal complex obtainable by contacting a compound represented by the following general formula [I] or [II] with a transition metal compound containing a transition metal belonging to 9th, 10th or 11th group in the periodic table: wherein R1, R2, R3 and R4 in the general formula [I] or [II], each independently represent (i) hydrogen, (ii) a halogen, (iii) a linear alkyl having 1 to 30 carbon atoms or the like, which optionally has one selected from the group consisting of a heteroatom and a group containing a heteroatom, or (iv) OR9 or the like; R5 and R6 each independently represent a linear alkyl group having 7 to 30 carbon atoms or the like, which optionally has one selected from the group consisting of a heteroatom and a group containing a heteroatom; E1 represents phosphorus, arsenic or antimony; and X1 represents oxygen or sulfur, and wherein, in the general formula [I], Z represents hydrogen or a leaving group, and m represents a valence of Z.