Group 4 Metal Catalyst for Olefin Dimer Selectivity
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Solution Overview
Problem
There is a significant need for catalysts that can dimerize C8+ alpha-olefins with high yield and selectivity, as existing catalysts often produce a wide spectrum of molecular weights, including dimers, trimers, and tetramers, and fail to achieve optimal conversion and selectivity for dimer production.
Innovation Solution
A process involving a catalyst system comprising a Group 4 metal complex with a tetradentate [OSSO]-type bisphenolate ligand and a non-coordinating anion activator, which contacts C8+ alpha-olefins at elevated temperatures to produce oligomerized products with at least 30% by weight of alpha-olefin dimers and high vinylidene unsaturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dimerization catalysts are used, then oligomerization reaction occurs, but the product contains a wide spectrum of molecular weights (dimers, trimers, and tetramers) with low selectivity for dimers
Solution Approach 1:
The patent applies parameter changes by modifying the catalyst's chemical structure - specifically using Group 4 metal complexes with tetradentate [OSSO]-type bisphenolate ligands. This structural parameter change enables the catalyst to selectively dimerize C8+ alpha-olefins with high selectivity (at least 30% by weight of dimer in the oligomerized product), resolving the contradiction between achieving oligomerization and maintaining narrow molecular weight distribution.
2Productivity
If conventional catalysts are used, then oligomerization proceeds, but conversion and selectivity for dimer production are not optimal
Solution Approach 1:
The patent achieves optimal conversion and selectivity by changing the catalyst's chemical parameters - specifically employing Group 4 metal (Ti, Zr, Hf) complexes with tetradentate [OSSO]-type bisphenolate ligands. These parameter changes result in high dimer selectivity (at least 30% by weight) and high vinylidene unsaturation (at least 90 mol%), simultaneously improving productivity and manufacturing precision.
Solution Approach 2:
The patent uses composite catalyst systems combining Group 4 metal complexes with specific tetradentate [OSSO]-type bisphenolate ligands and non-coordinating anion activators. This composite material approach creates a synergistic effect that achieves both high conversion and high selectivity for dimer production, resolving the contradiction between productivity and manufacturing precision.
3Quantity of substance
If metallocene catalysts are used for polymerization, then high molecular weight polymers are produced, but lower molecular weight oligomers with high dimer selectivity are not achieved
Solution Approach 1:
The patent applies parameter changes by using Group 4 metal complexes with tetradentate [OSSO]-type bisphenolate ligands, which differ from conventional metallocene catalysts. This parameter change enables the production of lower molecular weight oligomers with high dimer selectivity (at least 30% by weight), specifically targeting the dimer fraction while maintaining controlled molecular weight distribution.
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 process achieves high selectivity and conversion for alpha-olefin dimers, producing oligomerized products with at least 30% by weight of dimers and 90 mol% vinylidene unsaturation, effectively addressing the need for efficient dimerization of C8+ alpha-olefins.
Implementation Method 1
contacting, at a temperature of 80° C. or more, one or more C8+ alpha-olefins with a catalyst system comprising activator and one or more catalyst compounds represented by the formula: [Group 4 metal complex with tetradentate [OSSO]-type bisphenolate ligand]
Implementation Method 2
M is a Group 4 metal; n is 1, 2, or 3; each of R1, R2, R3, R4, R5, R6, R7, and R8 is independently selected from hydrogen and C1 to C10 alkyl
Data Source
AI summary
A process for producing alpha-olefin dimers comprises contacting, at a temperature of 80° C. or more, a feedstock comprising at least one C8+ (linear) alpha-olefin with a catalyst system comprising activator and one or more catalyst compounds represented by the formula:where M is a Group 4 metal; n is 1, 2, or 3; RA is hydrogen or a C1 to C10 alkyl; each of R1, R2, R3, R4, R5, R6, R7, and R8 is independently selected from hydrogen and C1 to C10 alkyl; each X is independently selected from the group consisting of hydrocarbyl radicals having from 1 to 20 carbon atoms, hydrides, amides, alkoxides, sulfides, phosphides, halides, and a combination thereof, (two X's may form a part of a fused ring or a ring system), the contacting being conducted under conditions effective to oligomerize at least part of C8+ alpha-olefin to produce an oligomerized product containing at least 30 wt % of the alpha-olefin dimer and at least 80 mol % of vinylidene unsaturation, where the conversion of the alpha olefin is at least 10 wt %, based upon the weight of the alpha olefin monomer entering the reactor and the weight of dimer produced.