Modified Alumina Conversion of 2-Ethyl-1-Butene for Olefin Purity
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Solution Overview
Problem
Conventional separation processes struggle to achieve high purity levels of linear alpha olefins due to the close boiling points of impurities, such as 2-ethyl-1-butene, in the oligomerization reaction products, necessitating improved purification methods.
Innovation Solution
A catalytic process using a modified alumina catalyst to isomerize 2-ethyl-1-butene to cis- or trans-3-methyl-2-pentene, followed by periodic regeneration in a non-oxidizing environment to maintain catalyst performance and enhance separation efficiency in distillation columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation columns are used to separate linear alpha olefins from impurities, then the separation process is simple, but the purity level cannot exceed 99.5 wt.% due to close boiling points of impurities
Solution Approach 1:
The patent applies preliminary action by using an isomerization catalyst to convert 2-ethyl-1-butene impurity into 3-methyl-2-pentene before the distillation process. This pre-treatment step modifies the impurity's boiling point characteristics, creating a greater separation gap between the impurity and the desired linear alpha olefin products, thereby enabling higher purity levels with conventional distillation equipment.
Solution Approach 2:
The patent changes the chemical parameter of the impurity by converting it from 2-ethyl-1-butene to 3-methyl-2-pentene through isomerization. This parameter change alters the impurity's physical properties (boiling point), making it more easily separable from the product stream through distillation, thus achieving >99.5 wt.% purity without requiring overly complex separation systems.
2Productivity
If 2-ethyl-1-butene is directly removed from the product stream, then the separation is straightforward, but the impurity's close boiling point to the product makes effective removal difficult
Solution Approach 1:
The patent introduces an isomerization catalyst as an intermediary substance that facilitates the conversion of the difficult-to-remove impurity (2-ethyl-1-butene) into an easier-to-remove form (3-methyl-2-pentene). This intermediary catalyst enables the impurity to be removed more efficiently through subsequent distillation, significantly improving purification efficiency without directly removing the original impurity.
3Duration of action of stationary object
If the alumina catalyst is used continuously without regeneration, then the process is simple, but the catalyst performance degrades over time
Solution Approach 1:
The patent implements periodic action by introducing regeneration cycles at scheduled intervals during catalyst operation. Instead of continuous operation, the catalyst undergoes periodic regeneration treatments that restore its activity and prevent degradation. This periodic maintenance approach extends catalyst life and maintains reliable performance levels throughout the operational period.
Solution Approach 2:
The patent applies discarding and recovering by periodically removing deactivated catalyst material and restoring active sites through regeneration processes. This cycle of discarding deactivated portions and recovering active catalytic sites maintains catalyst reliability over extended periods, preventing permanent degradation and extending operational lifespan.
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 process achieves high purity levels of linear alpha olefins, such as 1-hexene, exceeding 99.5 wt.%, by effectively converting impurities into more easily removable isomers, thereby reducing the number of distillation stages required.
Implementation Method 1
use of a modified alumina to isomerize 2-ethyl-1-butene to an isomer that is more easily removed from 1-hexene by distillation
Implementation Method 2
the effluent from the reactor used to produce the linear alpha olefins is directed to one or more distillation columns to separate the various fractions of linear alpha olefins
Implementation Method 3
periodically regenerating the modified alumina catalyst by stopping the feeding step and introducing a non-oxidizing environment to the reactor at time on stream intervals of no more than about 200 hours
Data Source
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AI summary
The disclosure provides a catalytic process for selective isomerization of 2-ethyl-1-butene in a linear alpha olefin stream that includes feeding a linear alpha olefin stream comprising a linear alpha olefin and 2-ethyl-1-butene to a reactor housing a modified alumina catalyst to isomerize at least a portion of the 2-ethyl-1-butene to cis- or trans-3-methyl-2-pentene, the period during which said feeding occurs being time on stream; withdrawing an effluent from the reactor containing less 2-ethyl-1-butene than the linear alpha olefin stream; and periodically regenerating the modified alumina catalyst by introducing a non-oxidizing environment to the reactor at time on stream intervals of no more than about 200 hours, wherein the reactor is subjected to the non-oxidizing environment for a time period of about 15 hours or greater and wherein the non-oxidizing environment has a temperature of about 250 °C or greater for at least a portion of the time period.