Chromium Catalyst Oligomerization Polymer Reduction
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Solution Overview
Problem
The development of alpha olefin oligomerization techniques that do not use triethylaluminum (TEA) as a catalyst faces challenges in matching the economics and efficiency of TEA-based methods, and alternative techniques require extensive secondary processing to recover linear alpha olefins from undesired fractions.
Innovation Solution
A process utilizing a catalyst system comprising a chromium component, a heteroatomic ligand, and an aluminoxane, or a heteroatomic ligand chromium compound complex, in the presence of an organic reaction medium and optionally hydrogen, to selectively form ethylene oligomers without forming ethylene oligomers in-situ, thereby improving the efficiency and reducing polymer formation during reaction zone startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If alternative oligomerization techniques are used to avoid triethylaluminum, then catalyst safety and environmental performance improve, but production efficiency and economic viability worsen
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using chromium compounds with heteroatomic ligands (O, N, S) instead of triethylaluminum, and by controlling the presence/absence of C3+ olefins during different reaction phases. This parameter change enables both safe catalysis without TEA and maintained productivity through optimized reaction conditions
Solution Approach 2:
The patent applies preliminary action by introducing C3+ olefins into the reaction zone before starting the oligomerization reaction. This preliminary presence of C3+ olefins prevents polymer formation and maintains catalyst activity, thereby ensuring both safety and productivity from the start of the process
2Productivity
If homogeneous catalyst systems are used for oligomerization, then catalyst activity improves, but product separation complexity worsens
Solution Approach 1:
The patent changes the physical state parameter of the catalyst system from homogeneous to heterogeneous by using solid chromium compound complexes supported on materials. This allows the catalyst to remain active while enabling simple separation of products from the catalyst phase, reducing secondary processing complexity
Solution Approach 2:
The patent segments the catalyst into distinct phases - the chromium compound complex on support material - allowing the catalytic function to be separated from the product mixture. This segmentation enables easy product recovery without extensive secondary processing while maintaining catalyst activity
3Manufacturing precision
If polymer formation is reduced during reaction zone startup, then linear alpha olefin selectivity improves, but reactor operation stability worsens
Solution Approach 1:
The patent introduces C3+ olefins into the reaction zone before starting the oligomerization reaction. This preliminary action ensures that the catalyst is in the correct state for selective oligomerization from the beginning, improving olefin selectivity while maintaining stable reactor operation through controlled reaction conditions
Solution Approach 2:
The patent employs feedback control by monitoring the oligomerization reaction conditions and adjusting the presence of C3+ olefins and reaction parameters to maintain both high selectivity and stable operation. The system responds to reaction progress to optimize performance throughout the process
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 approach enhances the production of linear alpha olefins by reducing polymer formation and improving reactor operation, leading to increased hexene and octene productivity and preventing fouling of reaction zone components.
Implementation Method 1
a catalyst system comprising (a) a chromium component comprising a chromium compound, (b) a heteroatomic ligand, and (c) an aluminoxane
Data Source
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AI summary
Disclosed herein are processes, systems, and reaction systems for the oligomerization of ethylene to form an ethylene oligomer product in a reaction zone using a catalyst system having i) a chromium component comprising a heteroatomic ligand chromium compound complex of the type disclosed herein, and ii) an aluminoxane. A C3+ olefin can be present in the reaction zone for a period of time, where the C3+ olefin is not an ethylene oligomer formed in-situ within the reaction zone.