Lewis Acid-Base Pair Catalytic Initiator for Epoxide Polymerization
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Solution Overview
Problem
Current Lewis acid-base pairs exhibit low catalytic activity and poor control in epoxide homopolymerization and copolymerization reactions, leading to unpredictable molecular weight and wide molecular weight distribution, as well as slow insertion rates of carbon dioxide, which limits the synthesis of well-defined polymeric materials.
Innovation Solution
A Lewis acid-base pair comprising a boron- or aluminum-containing Lewis acid and a tertiary amine Lewis base with moderate alkalinity, enhancing the formation of polymerization active centers and shifting the polymerization mode to 'fast initiation, fast growth', allowing for precise control of epoxide homopolymerization and copolymerization reactions to produce polyethers, polyesters, and polycarbonates with well-defined structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional Lewis acid-base pairs are used for epoxide polymerization, then polymerization can proceed, but the catalytic activity is low with TOF only reaching 49-113 h−1
Solution Approach 1:
The patent changes the chemical parameters of the Lewis acid-base pair by selecting specific combinations (BF3·OEt2 with Et3N, AlCl3 with Et3N, or B(C6F5)3 with Et3N) to achieve dramatically higher catalytic activity with TOF up to 22,500 h−1, resolving the contradiction between low productivity and time loss in conventional systems
2Manufacturing precision
If conventional Lewis acid-base pairs are used, then polymerization can occur, but the initiation efficiency is low resulting in unpredictable molecular weight and wide molecular weight distribution
Solution Approach 1:
The patent changes the chemical parameters by selecting specific Lewis acid-base pairs with appropriate strength matching, which improves initiation efficiency and enables precise control of molecular weight and narrow molecular weight distribution, resolving the contradiction between manufacturing precision and reliability
3Manufacturing precision
If conventional Lewis acid-base pairs are used for CO2 copolymerization, then copolymerization can proceed, but the insertion rate of CO2 is slow leading to poor alternating structure formation
Solution Approach 1:
The patent changes the chemical parameters of the catalytic system by selecting Lewis acid-base pairs with optimized acidity and basicity strengths, which dramatically increases CO2 insertion rate and achieves fully alternating structures, resolving the contradiction between manufacturing precision and 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 Lewis acid-base pair achieves significantly higher catalytic activity, with conversion frequencies up to 22,500 h−1, enabling the synthesis of polymers with fully alternating structures and reduced production costs through efficient chain transfer agents, resulting in polymers with precise molecular weight and narrow distribution.
Implementation Method 1
Lewis acid-base pair catalytic initiator... can be used to catalyze epoxide homopolymerization reactions as well as epoxide copolymerization reactions to synthesize polyethers, polyesters, polycarbonates
Data Source
AI summary
The present disclosure provides a Lewis acid-base pair catalytic initiator and an application thereof. The Lewis acid-base pair catalytic initiator includes a Lewis acid and a Lewis base, the Lewis acid having a structural general formula as shown in formula (I) and the Lewis base having a structural general formula as shown in formula (II); wherein: the A is selected from element Baron or element Aluminum; the R1, R2, R3, R4 are independently selected from alkyl, alkoxy, aryl or halogen groups; the alkyl or alkoxy have a carbon number being equal to or greater than 1 to equal to or less than 16; the aryl contains substituents with the number being equal to or less than 5, the substituents being selected from methyl, methoxy or halogen; n is selected from an integer from 1 to 16.