Alpha-Olefin Low Polymer Production via Halogenated Catalyst Circulation
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Solution Overview
Problem
The existing methods for producing α-olefin low polymers, such as 1-hexene through ethylene trimerization, suffer from low selectivity and purity, leading to significant impurities in the product, which affects the quality and efficiency of industrial production.
Innovation Solution
A method involving a catalyst system comprising a transition metal-containing compound, an aluminium-containing compound, and a halogen-substituted hydrocarbon, where a halogen-substituted olefin is circulated within specific molar ratios to improve selectivity and purity, utilizing a chromium-based catalyst with nitrogen-containing compounds to enhance reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalyst systems are used for ethylene trimerization, then production activity is maintained, but product selectivity and purity are low
Solution Approach 1:
The invention changes the chemical parameters of the catalyst system by introducing a halogen-containing compound (such as CrCl3 or CrCl2) in combination with an organic ligand. This parameter change transforms the catalyst's selectivity characteristics, enabling high-selectivity trimerization to 1-hexene while suppressing side reactions that produce impurities.
Solution Approach 2:
The invention employs a composite catalyst system consisting of multiple components: chromium compound, organic ligand (such as beta-diketonate or amine), and halogen-containing compound. This composite approach creates synergistic effects that simultaneously achieve high activity and high selectivity, resolving the contradiction between production efficiency and product purity.
2Manufacturing precision
If existing production methods are used, then continuous production is possible, but selectivity improves only after long operation time
Solution Approach 1:
The invention performs preliminary optimization of the catalyst composition before production begins. By pre-configuring the specific ratios of chromium compound, organic ligand, and halogen-containing compound, the system achieves high selectivity from the start of operation without requiring extended warm-up or stabilization periods.
Solution Approach 2:
The invention modifies the initial catalyst system parameters to include specific halogen-containing compounds and organic ligands, which fundamentally change the reaction pathway selectivity. This parameter optimization ensures high 1-hexene selectivity is achieved immediately upon startup, eliminating the need for long operational periods to improve selectivity.
3Manufacturing precision
If halogen-containing compounds are used in catalyst, then selectivity improves, but halogenated olefin side products are generated
Solution Approach 1:
The invention optimizes the parameters of halogen-containing compound selection and concentration to achieve a balance where selectivity is maximized while side product formation is minimized. By carefully controlling the type and amount of halogen compound used, the system achieves high 1-hexene selectivity with acceptable side product levels.
Solution Approach 2:
The invention applies local quality control by using specific halogen-containing compounds (such as CrCl3 or CrCl2) in combination with organic ligands that create a localized catalytic environment favorable for trimerization while suppressing halogenated side product formation. The organic ligand modifies the local chemical environment around the chromium center to enhance selectivity.
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 significantly enhances the selectivity and purity of the α-olefin low polymer production while maintaining catalyst activity within acceptable ranges, improving the overall industrial process efficiency.
Implementation Method 1
a catalyst containing a chromium compound and a halogen-containing compound
Data Source
AI summary
The present invention relates to a method for producing an .alpha.-olefin low polymer through low polymerization reaction of an .alpha.-olefin in the presence of a catalyst containing a transition metal-containing compound, an aluminum-containing compound and a hydrocarbon having 2 or more carbon atoms and substituted with a halogen atom, and a solvent, which comprises a reaction step, a purification step and a circulation step of circulating the unreacted raw material .alpha.-olefin and the solvent from the purification step to the reaction step; and in which the amount of the olefin having 2 or more carbon atoms and substituted with a halogen atom that is supplied from the circulation step to the reaction step is within a range of from 0.1 to less than 200 (molar ratio) relative to the amount of the transition metal in the reaction step.