Chromium Catalyst Ligand Design for Selective Olefin Oligomerization
Solution Overview
Problem
Existing catalyst systems for the selective oligomerization of ethylene have insufficient selectivity and catalytic activity for producing 1-hexene and 1-octene, requiring additional separation processes and resulting in inefficient production of linear alpha-olefins.
Innovation Solution
A novel ligand compound and organic chromium compound with specific chemical structures, including branched alkylene or alkenylene linkers, are used in a catalyst system with a cocatalyst to enhance the selectivity and catalytic activity for oligomerization reactions, allowing for the efficient production of alpha-olefins like 1-hexene and 1-octene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the Shell higher olefin process is used to prepare linear alpha-olefins, then various alpha-olefins of different lengths can be synthesized, but additional separation processes are required to obtain a specific alpha-olefin due to Schultz-Flory distribution
Solution Approach 1:
The patent applies local quality by designing ligands with specific local structural features (branched alkylene or alkenylene groups with 3-10 carbon atoms) that create a localized steric environment around the chromium center. This local structural modification enables selective binding and activation of specific olefin substrates, achieving high selectivity for 1-hexene or 1-octene without requiring separation processes
2Manufacturing precision
If previously known catalyst systems are used for selective oligomerization of ethylene, then some selectivity can be achieved, but the selectivity to 1-hexene and 1-octene is insufficient and catalytic activity is poor
Solution Approach 1:
The patent employs composite materials by combining chromium compounds with specifically designed ligand systems comprising nitrogen, phosphorus/arsenic/antimony, and branched alkylene/alkenylene groups. This composite ligand structure creates a synergistic effect where the nitrogen donor provides electronic stabilization while the phosphorus/arsenic/antimony donors and branched linker provide steric control, achieving both high selectivity (29) and high catalytic activity (39) simultaneously
Solution Approach 2:
The patent applies parameter changes by systematically varying the ligand structure parameters including the type of donor atoms (P, As, Sb), the carbon atom number in the linker (3-10), and the branching pattern of the alkylene group. These parameter modifications optimize the electronic and steric properties of the catalyst, enabling high selectivity for specific oligomerization products while maintaining high catalytic activity
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 catalyst system exhibits high selectivity and catalytic activity, enabling more efficient production of alpha-olefins with improved selectivity to 1-hexene and 1-octene, reducing the need for additional separation processes and enhancing the overall production efficiency.
Implementation Method 1
a catalyst system for oligomerization of olefins including the ligand compound and the organic chromium compound, and a method for oligomerizing olefins using the same
Data Source
AI summary
The present invention relates to a ligand compound, a catalyst system for oligomerization of olefins including the ligand compound and the organic chromium compound, and a method for oligomerizing olefins using the same. The catalyst system for olefin oligomerization according to the present invention invention exhibits high selectivity to 1-hexene or 1-octene while having excellent catalytic activity, thereby enabling more efficient production of alpha-olefins.