1,2-Phenylene Bridged Metallocene Catalysts for Olefin Polymerization
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Solution Overview
Problem
Existing metallocene catalysts face challenges in achieving high reactivity for alpha-olefin incorporation, particularly in copolymerization of ethylene with higher alpha-olefins like 1-hexene, while maintaining high molecular weight and yield.
Innovation Solution
A new family of substituted 1,2-phenylene bridged 1-indenyl 2-indenyl metallocene complexes is developed, which exhibits higher catalyst activity, increased 1-hexene incorporation, and high molecular weight polymers when used in olefin polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing metallocene catalysts are used for copolymerization of ethylene with higher alpha-olefins like 1-hexene, then catalyst activity and molecular weight can be maintained, but reactivity towards alpha-olefin incorporation is insufficient
Solution Approach 1:
The patent applies local quality by introducing specific substituents (R1, R2, R3, R') at precise positions on the indenyl ligands and phenylene bridge. These localized structural modifications create specific electronic and steric environments at the active site that enhance alpha-olefin reactivity while preserving overall catalyst activity and molecular weight characteristics.
Solution Approach 2:
The patent employs parameter changes by systematically varying substituents R1, R2, R3, and R' to optimize catalyst performance. By adjusting these structural parameters, the catalyst achieves improved alpha-olefin incorporation reactivity while maintaining high catalyst activity and producing polymers with desired molecular weights.
2Quantity of substance
If alpha-olefin content in copolymer is increased, then copolymer composition is improved, but average molecular weight decreases
Solution Approach 1:
The patent uses parameter changes by modifying the catalyst structure through substituents R1, R2, R3, and R' to alter the polymerization kinetics. These structural parameters are optimized to enable high alpha-olefin incorporation while preventing premature chain termination, thus maintaining high molecular weight even at elevated comonomer contents.
Solution Approach 2:
The patent applies dynamics by creating a catalyst system that adapts to varying monomer feed compositions. The catalyst maintains stable activity and produces high molecular weight polymers across a range of alpha-olefin contents, demonstrating dynamic performance that overcomes the typical inverse relationship between comonomer content and molecular weight.
3Productivity
If reactivity towards alpha-olefins is increased, then less alpha-olefin is required to reach desired content, but catalyst structure complexity increases
Solution Approach 1:
The patent applies local quality by making targeted, localized modifications to the catalyst structure through specific substituents at defined positions. Rather than complex overall restructuring, precise local changes to R1, R2, R3, and R' groups achieve enhanced alpha-olefin reactivity with relatively simple structural modifications.
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 metallocene complexes demonstrate enhanced ethylene alpha-olefin copolymerization performance, achieving high yields with high 1-hexene reactivity and maintaining high molecular weight, addressing the limitations of existing catalysts.
Implementation Method 1
Metallocene complexes together with a cocatalyst form catalysts that are widely used for olefin polymerisation
Data Source
AI summary
The invention relates to a metallocene complex according to formula (I), (I) wherein R1 and R2 are independently selected from H, an alkyl or an aryl group, wherein R3 is a C1 -C10 alkyl group, wherein R' is selected from H, an alkyl group, an aryl group and wherein different R' substituents can be connected to form a ring structure and wherein B is a 1,2 phenylene bridging moiety, which can be optionally substituted, wherein Mt is selected from Ti, Zr and Hf, X is an anionic ligand, z is the number of X groups and equals the valence of Mt minus 2. The invention also relates to a catalyst comprising the reaction product of the metallocene complex and a cocatalyst. Further the invention relates to a (co)polymerisation process of olefinic monomers.