Butene Oligomer Preparation Using Organometal Catalyst
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Solution Overview
Problem
Conventional methods for preparing butene oligomers using cationic polymerization face challenges such as corrosive catalysts, toxic boron-based Lewis acids, and difficulties in controlling molecular weight and catalyst removal, leading to product quality issues and environmental concerns.
Innovation Solution
A method employing an organometal catalyst with a group 13 metal and bulky borate-based anion, using a mixture solvent of halogenated and nonpolar hydrocarbons to control molecular weight and facilitate catalyst removal through simple filtering, without generating halogen salts or requiring expensive metal reagents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Lewis acid catalyst (AlX3, BX3) is used for cationic polymerization, then the polymerization reaction can be initiated, but halogen components (HCl, HF) are produced during quenching which degrade product quality and require additional washing steps generating large amounts of waste water
Solution Approach 1:
The patent removes the harmful halogen-containing Lewis acid catalyst (BX3, AlX3) from the polymerization system and replaces it with a non-halogenated alternative. The quenching step that produces HCl and HF is eliminated by using a different catalyst system that can be quenched with water without producing harmful halogen components, thereby extracting the harmful element from the process.
Solution Approach 2:
The patent converts the problematic quenching step into a beneficial process by using a non-halogenated catalyst that can be safely quenched with water. The water quenching now serves to terminate the reaction cleanly without producing harmful halogen components, and the base treatment step is optimized to minimize waste water generation while effectively removing catalyst residues.
2Productivity
If a boron-based Lewis acid catalyst (BF3) is used to polymerize high reactive butene oligomer, then the oligomer can be produced, but the catalyst is toxic and difficult to handle requiring preparation of composite catalysts which reduces activity over time
Solution Approach 1:
The patent employs an organometallic catalyst system with a bulky borate anion that is designed for single-use or limited-use applications. The catalyst is prepared fresh for each polymerization run and disposed of after use, eliminating the need for long-term storage and repeated handling of toxic BF3. This disposable approach prioritizes safety and ease of handling over catalyst reusability.
Solution Approach 2:
The patent uses a composite catalyst system consisting of a metal cation (M+) paired with a bulky borate anion (BArF4- or similar). This composite structure combines the electrophilic activity needed for polymerization with the steric protection that prevents decomposition and reduces toxicity. The bulky anion acts as a protective shell around the reactive metal center, making the overall catalyst system safer to handle while maintaining activity.
3Ease of manufacture
If a metal complex is prepared using conventional silver reagents (AgNO3, Ag2CO3) to create catalyst precursors, then the catalyst can be formed, but the process requires expensive reagents and produces metal salts that are difficult to remove completely from the final product
Solution Approach 1:
The patent removes expensive silver reagents (AgNO3, Ag2CO3) from the catalyst preparation process and replaces them with cheaper, more easily removable metal salts. The harmful element (silver) is extracted from the process, and alternative metals are used that can be more effectively removed during product purification, thereby improving both cost-effectiveness and product purity.
Solution Approach 2:
The patent changes the metal parameter in the catalyst preparation process from silver to alternative metals that are cheaper and more easily removable. By changing the metal identity parameter, the process achieves better cost-performance ratio and easier purification, as the alternative metal salts can be more effectively separated from the final oligomer product through standard purification techniques.
4Productivity
If the reaction time is extended to achieve high conversion ratio with solvent-ligated organometal catalyst, then conversion increases, but structural isomerization occurs through reaction of product with catalyst reducing exo-content and competitiveness
Solution Approach 1:
The patent changes the catalyst structure parameter by introducing a bulky borate anion with specific steric properties. This structural modification allows the reaction to proceed at optimized rates without excessive isomerization. The bulky anion creates a sterically constrained environment that favors direct polymerization over isomerization reactions, enabling high conversion while maintaining high exo-content.
Solution Approach 2:
The patent optimizes the reaction conditions dynamically by adjusting parameters such as temperature, monomer-to-catalyst ratio, and reaction time to achieve the optimal balance between conversion and selectivity. The system is designed to operate in a dynamic regime where the catalyst remains active enough to achieve high conversion but the reaction conditions are controlled to minimize isomerization side reactions.
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 efficiently produces butene oligomers with controlled low molecular weights and high exo-content, reducing toxicity and waste, while maintaining catalyst activity and simplifying the production process.
Implementation Method 1
In a process for preparing an oligomer or a polymer by the cationic polymerization of monomers, a propagating polymer chain includes an active moiety which has a positive charge. For example, the active moiety may be a carbenium ion (carbon cation) or an oxonium ion.
Implementation Method 2
L is one or more selected from the group consisting of acetonitrile, propionitrile, 2-methylpropanenitrile, trimethylacetonitrile, benzonitrile, dialkyl ether, pyridine, dimethylformamide, dimethyl sulfoxide, nitromethane, nitrobenzene and the derivatives thereof, and a coordinating solvent molecule in which an unshared electron pair of oxygen, nitrogen or carbon makes a coordination bond with M
Data Source
AI summary
The present invention provides a method for preparing a butene oligomer including a step of oligomerizing a polymerization solution including a halogenated hydrocarbon solvent, a nonpolar hydrocarbon solvent and an isobutene monomer in the presence of an organometal catalyst.