Polyether Polyol Synthesis via Fluoroalkyl Boron Catalysts
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Solution Overview
Problem
The existing methods for producing polyether polyols using double-metal cyanide (DMC) catalysts are hindered by a slow activation process, leading to increased productivity losses and potential batch failures. Additionally, conventional Lewis acid catalysts like boron trifluoride result in undesirable side-reactions, such as the formation of volatile low molecular weight cyclic ethers and acetal linkages, which complicate the production process.
Innovation Solution
The use of a Lewis acid catalyst with a specific formula, such as M(R1)1(R2)1(R3)1(R4)0 or 1, where M is boron or other metals, and R1, R2, and R3 include fluoroalkyl-substituted phenyl groups, minimizes side-reactions and allows for precise control of the polymerization reaction. This catalyst system can be used alone or in combination with a DMC catalyst to produce polyether polyols with reduced acetal linkages and improved molecular weight control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a double-metal cyanide (DMC) catalyst is used to produce polyether polyols, then the catalyst provides high activity for polymerization, but the catalyst requires a long induction period to activate, reducing productivity
Solution Approach 1:
The patent introduces a Lewis acid catalyst (such as boron trifluoride, trifluoromethane boronic acid, or their adducts with ethers or esters) that is pre-activated before the DMC catalyst. This Lewis acid catalyst immediately initiates polymerization upon contact with alkylene oxide, eliminating the induction period problem. The Lewis acid catalyst serves as a preliminary action that ensures immediate productivity while the DMC catalyst provides sustained high activity throughout the reaction.
2Power
If conventional Lewis acid catalysts like boron trifluoride are used for polymerization, then the catalyst provides high activity, but it causes undesirable side-reactions forming volatile low molecular weight cyclic ethers and requires high catalyst loading
Solution Approach 1:
The patent modifies the parameters of the Lewis acid catalyst by using specifically boron trifluoride, trifluoromethane boronic acid, or their adducts with ethers or esters, and controls the reaction conditions (temperature, catalyst loading, monomer concentration) to optimize the balance between activity and side-reactions. These parameter changes enable the Lewis acid catalyst to provide high activity while minimizing the formation of volatile cyclic ethers and other harmful side-products.
3Ease of manufacture
If conventional Lewis acid catalysts are used, then the catalyst can initiate polymerization, but it leads to catalyst decomposition releasing corrosive HF and incorporating fluorine atoms in the polymer backbone
Solution Approach 1:
The patent employs a Lewis acid catalyst system (boron trifluoride, trifluoromethane boronic acid, or their adducts) that can be easily introduced and removed from the reaction system. These catalysts are used in controlled amounts and can be neutralized or removed through standard workup procedures, avoiding the need for complex catalyst recovery systems. The catalyst serves its purpose efficiently and can be disposed of or neutralized without causing extensive corrosion or fluorine incorporation issues.
4Ease of operation
If tris (pentafluorophenyl)borane catalyst is used for alkoxylation, then the catalyst is not corrosive and easy to handle, but it causes side-reactions forming aldehydes and acetal linkages in the polyol backbone
Solution Approach 1:
The patent combines the DMC catalyst system with a Lewis acid catalyst (boron trifluoride, trifluoromethane boronic acid, or their adducts) to create a dual catalyst system. This combination merges the advantages of both catalyst types: the DMC catalyst provides high activity and the Lewis acid catalyst suppresses the formation of aldehydes and acetals. The synergistic effect of the combined catalyst system eliminates the harmful side-reactions while maintaining ease of handling and high productivity.
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 system effectively reduces the formation of undesirable side-products, such as aldehydes and acetals, while maintaining high molecular weight and productivity. This results in polyether polyols that require less finishing steps and are suitable for producing high-quality polyurethane products.
Implementation Method 1
The use of a Lewis acid catalyst with a specific formula, such as M(R1)1(R2)1(R3)1(R4)0 or 1, where M is boron or other metals, and R1, R2, and R3 include fluoroalkyl-substituted phenyl groups, minimizes side-reactions and allows for precise control of the polymerization reaction
Data Source
AI summary
A method of producing a polyether polyol includes reacting a low molecular weight initiator with one or more monomers in the presence of a polymerization catalyst, and the low molecular weight initiator has a nominal hydroxyl functionality of at least 2. The one or more monomers includes at least one selected from propylene oxide and butylene oxide. The polymerization catalyst is a Lewis acid catalyst having the general formula M(R1)1(R2)1(R3)1(R4)0 or 1, whereas M is boron, aluminum, indium, bismuth or erbium, R1, R2, R3, and R4 are each independent, R1 includes a fluoroalkyl-substituted phenyl group, R2 incudes a fluoroalkyl-substituted phenyl group or a fluoro/chloro-substituted phenyl group, R3 includes a fluoroalkyl-substituted phenyl group or a fluoro/chloro-substituted phenyl group, and optional R4 includes a functional group or functional polymer group, R1 being different from at least one of R2 and R3.