Linear Alpha-Olefin Purity via Additive Mediator
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Solution Overview
Problem
Existing methods for preparing linear alpha-olefins through ethylene oligomerization suffer from product degradation due to unwanted side reactions, high installation and maintenance costs for mixing devices, and the formation of organic chlorides and alkylated toluenes, which compromise product purity and efficiency.
Innovation Solution
A method involving the use of specific additives such as alcohols, polyethylene glycols, and amines in the reactor outlet stream before catalyst deactivation with caustic, ensuring a minimum residence time to prevent side reactions and facilitate efficient catalyst removal, thereby improving product purity and reducing energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalyst deactivation is performed quickly and effectively, then product degradation by unwanted side reactions is reduced, but high installation and maintenance costs are incurred for mixing devices
Solution Approach 1:
The patent introduces an intermediary substance (amine or alcohol) that mediates between the catalyst and caustic. This intermediary forms a complex with the catalyst first, then reacts with caustic to deactivate the catalyst. This mechanism allows effective catalyst deactivation without requiring intensive mixing devices, as the chemical reaction occurs in the bulk phase rather than requiring intense mixing at the molecular level.
Solution Approach 2:
The patent applies preliminary action by adding the amine or alcohol additive to the reactor outlet stream before the catalyst deactivation step. This preliminary addition ensures that the catalyst is already complexed with the intermediary substance when caustic is introduced, facilitating smoother and more effective deactivation without requiring complex mixing equipment.
2Productivity
If static or active mixing devices are used to enhance catalyst removal efficiency, then catalyst removal is improved, but installation costs and maintenance requirements increase
Solution Approach 1:
The amine or alcohol acts as a chemical intermediary that facilitates catalyst removal through chemical complexation rather than mechanical mixing. The intermediary forms a soluble complex with the catalyst, allowing efficient removal without requiring static or active mixing devices, thereby reducing installation and maintenance costs.
Solution Approach 2:
The patent changes the chemical parameters of the system by introducing the amine or alcohol additive, which alters the catalyst's chemical properties and使其 more susceptible to deactivation by caustic. This chemical parameter change enables efficient catalyst removal through simple mixing rather than complex mechanical systems.
3Productivity
If conventional deactivation methods are used, then catalyst removal is achieved, but formation of organic chlorides and alkylated toluenes occurs
Solution Approach 1:
The amine or alcohol intermediary prevents unwanted side reactions by first complexing with the catalyst and then reacting with caustic. This intermediary mechanism blocks the catalyst from catalyzing unwanted side reactions such as Friedel-Crafts alkylation and organic chloride formation, while still achieving effective catalyst removal.
Solution Approach 2:
The patent applies preliminary anti-action by introducing the amine or alcohol additive before caustic deactivation. This preliminary step prevents the catalyst from catalyzing unwanted side reactions during the deactivation process. The intermediary substance proactively blocks harmful reactions before they can occur, rather than reacting after they have started.
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 method effectively suppresses unwanted side reactions, enhances catalyst removal efficiency, and prevents the formation of organic chlorides and alkylated toluenes, leading to improved product purity and reduced maintenance needs, while allowing for online cleaning of equipment.
Implementation Method 1
dosage of an additive selected from the group consisting of amines, alcohol and surfactants into the reactor outlet stream prior to mixing with the caustic
Implementation Method 2
deactivating the catalyst with caustic and removing the deactivated catalyst from the reactor outlet stream
Implementation Method 3
The catalyst may be preferably deactivated by caustic
Implementation Method 4
suppression of unwanted side reactions, less energy requirements for mixing, no requirement for sophisticated mixing devices and allowing Online Cleaning of piping and equipment. Also, the formation of organic chlorides and of alkylated toluenes by Friedel-Crafts-alkylation shall be prevented
Data Source
AI summary
The present invention relates to a method for preparing linear alpha-olefins (LAO) by oligomerization of ethylene in the presence of a solvent and homogeneous catalyst, comprising the steps of:(i) feeding ethylene, solvent and catalyst into an oligomerization reactor,(ii) oligomerizing the ethylene in the reactor,(iii) removing a reactor outlet stream comprising solvent, linear alpha-olefins, optionally unreacted ethylene and catalyst from the reactor via a reactor outlet piping system,(iv) dosing at least one additive selected from the group consisting of alcohols, poly-ethylene glycols, polyethylene glycol monoethers, polyethylene glycol diethers, polyamines, amines, amino alcohols and surfactants,(v) transferring the reactor outlet stream containing the additive to a catalyst deactivation and removal section, and(vi) deactivating the catalyst with caustic and removing the deactivated catalyst from the reactor outlet stream,wherein the residence time of the additive in the reactor outlet stream prior to mixing with caustic is at least 1 second preferably at least 5 seconds, more preferably at least 10 seconds.