Oxonium Catalyst Composition for Polyisobutene Polymerization
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Solution Overview
Problem
Existing methods for preparing polyisobutene face challenges such as low molecular weight, reduced exo-content, and product quality degradation due to the use of toxic boron-based Lewis acid catalysts, which also generate halogen components and require extensive washing, leading to wastewater issues.
Innovation Solution
A catalyst composition comprising a catalyst represented by Formula 1, which includes a linear C3 or C4-C12 alkyl group, and a nitrile-based additive, is used for the cationic polymerization of isobutene. This composition allows for high molecular weight polyisobutene production with exo-content of 80 mol % or more, under moderate reaction conditions, and enables easy catalyst removal through filtering, reducing waste water generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a boron-based Lewis acid catalyst such as BF3 is used for cationic polymerization, then the polymerization reactivity and conversion ratio are improved, but the catalyst becomes toxic, corrosive, and difficult to handle, requiring extensive washing and producing large amounts of wastewater
Solution Approach 1:
The patent introduces a nitrile-based additive as an intermediary substance that mediates between the catalyst and the polymerization system. This additive modifies the catalyst's behavior, reducing its toxicity and corrosiveness while maintaining polymerization activity. The additive acts as a bridge that allows the catalyst to function without directly contacting the product in harmful ways.
Solution Approach 2:
The patent changes the chemical parameters of the catalyst system by introducing a nitrile-based additive that modifies the catalyst's properties. This parameter change transforms the catalyst from a highly toxic and corrosive boron-based Lewis acid into a less harmful system that maintains polymerization efficiency while reducing environmental and safety concerns.
2Productivity
If a Lewis acid catalyst is used for cationic polymerization, then the polymerization reaction proceeds efficiently, but a large amount of base is required for catalyst removal, and additional washing with water is needed, producing large amounts of wastewater
Solution Approach 1:
The nitrile-based additive serves as an intermediary that facilitates easier catalyst removal. Instead of requiring large amounts of base and water for catalyst removal, the additive enables the catalyst to be removed through simpler means, significantly reducing wastewater production while maintaining polymerization efficiency.
Solution Approach 2:
The patent enables more effective discarding of the catalyst through the nitrile-based additive. The additive facilitates the separation and removal of the catalyst from the product stream, allowing for cleaner product recovery with minimal wastewater, thus reducing the loss of substance and environmental impact.
3Productivity
If the reaction time is extended to increase conversion ratio, then more polymer is produced, but structural isomerization occurs through product-catalyst reaction, reducing exo-content and product quality
Solution Approach 1:
The nitrile-based additive acts as an intermediary that protects the product from unwanted catalyst reactions. By modifying the catalyst's interaction with the product, the additive prevents structural isomerization during extended reaction times, thereby maintaining high exo-content and product quality while achieving high conversion ratios.
Solution Approach 2:
The additive provides beforehand cushioning by preventing the catalyst from reacting with the product in harmful ways. This protective effect is established during the reaction process, cushioning against the potential for structural isomerization and ensuring product quality is maintained throughout extended reaction times.
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 proposed catalyst composition achieves high reactivity and excellent polymerization conversion ratios, producing polyisobutene with desired molecular weight and exo-content, while minimizing catalyst residue and wastewater production.
Implementation Method 1
in a process for preparing an oligomer or a polymer by the cationic polymerization of a monomer, a propagating polymer chain includes an active moiety which has a positive charge. For example, the active moiety may be a carbenium ion (carbocation) or an oxonium ion.
Implementation Method 2
the active moiety may be a carbenium ion (carbocation) or an oxonium ion
Data Source
AI summary
The present invention relates to a catalyst composition including an oxonium ion-based catalyst represented by the following Formula 1, and an additive, and a method for preparing polyisobutene using the same:wherein R, R1 to R4, and o, p, q and r are described herein.