Alkane Oligomerization via Iridium Dehydrogenation and Nickel Coupling
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Solution Overview
Problem
Current organometallic catalyst systems for producing linear α-olefins suffer from low selectivity, leading to inefficient production of desired chain lengths and the formation of polymer co-products, which reduces yield and increases production costs.
Innovation Solution
An integrated process using an iridium catalyst complex with a benzimidazolyl-containing ligand for dehydrogenation, followed by oligomerization with a nickel, platinum, or palladium catalyst complex having a nitrogen-containing bi- or tridentate ligand, and subsequent hydrogenation, all occurring in a single reactor, to efficiently produce oligomeric alkanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional organometallic catalyst systems are used for producing linear α-olefins, then the production process can proceed, but selectivity is low leading to inefficient production of desired chain lengths and formation of polymer co-products
Solution Approach 1:
The patent modifies the catalyst system parameters by using specific iridium complexes with cyclic alkyl(amino)carbene ligands, which fundamentally changes the catalytic behavior from conventional organometallic catalysts. This parameter change in catalyst composition achieves high selectivity for dimer and trimer production while eliminating polymer formation, directly resolving the contradiction between selectivity and productivity
Solution Approach 2:
The invention employs a composite catalyst system consisting of iridium metal center coordinated with cyclic alkyl(amino)carbene ligands. This composite structure combines the advantages of iridium's catalytic activity with the unique properties of the carbene ligands, creating a catalyst that simultaneously achieves high selectivity and productivity by controlling oligomerization to specific chain lengths without polymer formation
2Manufacturing precision
If chromium catalysts are used to improve selectivity for α-olefins, then selectivity improves, but polymer is formed as a co-product reducing yield and requiring frequent reactor cleaning
Solution Approach 1:
The patent extracts and eliminates the polymer formation side reaction that plagues conventional chromium-catalyzed oligomerization. By using iridium catalysts with cyclic alkyl(amino)carbene ligands, the process selectively produces dimers and trimers while completely avoiding polymer co-products, thus taking out the harmful polymer formation and improving both selectivity and yield
Solution Approach 2:
The invention converts the potential harm of uncontrolled polymerization into a benefit by designing a catalyst system that specifically promotes oligomerization to desired chain lengths (dimers and trimers) while suppressing polymer formation. The iridium-carbene catalyst system transforms what would be a harmful side reaction into a controlled process that enhances selectivity and yield
3Manufacturing precision
If chromium catalysts are used to achieve selective α-olefin production, then selectivity improves, but polymer build-up in the reaction vessel severely hampers production efficiency
Solution Approach 1:
The patent converts the harmful polymer build-up issue into a benefit by designing an iridium-catalyzed system that selectively produces dimers and trimers without forming polymers. The cyclic alkyl(amino)carbene ligands on the iridium catalyst promote controlled oligomerization while preventing the uncontrolled polymerization that causes reactor fouling, thus improving both selectivity and production efficiency
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
This process enhances selectivity and efficiency, reducing waste and polymer formation, thereby improving the cost-effectiveness of oligomer production and maintaining reactor efficiency.
Implementation Method 1
contacting an alkane under dehydrogenation conditions in the presence of a dehydrogenation catalyst, e.g., an iridium catalyst complex
Implementation Method 2
contacting the olefins prepared in step (a) under oligomerization conditions in the presence of an oligomerization catalyst, e.g., a nickel, platinum or palladium metal catalyst complex
Implementation Method 3
followed by hydrogenation of the coupled olefinic products
Data Source
AI summary
Provided is a process for preparing oligomers from an alkane. The process comprises (a) contacting an alkane under dehydrogenation conditions in the presence of a dehydrogenation catalyst such as an iridium catalyst complex comprising iridium complexed with a benzimidiazolyl-containing ligand to form olefins, and (b) contacting the olefins prepared in step (a) under oligomerization conditions with an oligomerization catalyst such as a nickel, platinum or palladium metal catalyst complex comprising the metal complexed with a nitrogen containing bi- or tridentate ligand to prepare oligomers of the olefins, and hydrogenating the olefin oligomers. In one embodiment, the ligands of the catalyst complexes in step (a) and step (b) can be the same.