Bis(aryl)acetal Monomers for Polyacetal Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for synthesizing polyacetals are limited as they require acetal formation reactions that consume free hydroxyl groups and other functional groups, making it difficult to incorporate these groups into the polymer backbone without expensive protection/deprotection strategies.
Innovation Solution
The use of bis(aryl)acetals as monomers or comonomers in transition metal-catalyzed cross-coupling reactions, such as Suzuki coupling, allows for the synthesis of oligoacetals and polyacetals with acetal functional groups in the backbone, enabling the incorporation of free hydroxyl groups and other incompatible functional groups without relying on acetal formation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional acetal formation reactions are used to synthesize polyacetals, then acetal moieties can be formed during polymerization, but free hydroxyl groups and other functional groups are consumed and cannot be incorporated into the polymer backbone
Solution Approach 1:
The patent introduces bis(aryl)acetals as pre-formed monomers that contain the acetal functionality already built into the molecule. This preliminary formation of the acetal moiety before polymerization allows the functional groups (hydroxyl, carboxyl, amino) to be incorporated into the polymer backbone without being consumed during acetal formation, as the acetal functionality is pre-established in the monomer structure.
Solution Approach 2:
The patent uses transition metal catalysts (such as palladium, nickel, or copper catalysts) as intermediaries to facilitate the polymerization reaction. These catalysts enable the formation of polyacetals from bis(aryl)acetal monomers through mechanisms that do not require the consumption of free hydroxyl groups, allowing compatible functional groups to be preserved in the polymer backbone.
2Adaptability or versatility
If protection/deprotection strategies are used to incorporate incompatible functional groups, then functional groups can be included in the polymer, but the synthesis process becomes more complex and expensive
Solution Approach 1:
The patent extracts the acetal formation step from the polymerization process by using pre-formed bis(aryl)acetal monomers. This separation allows the polymerization to proceed without requiring protection/deprotection strategies, as the acetal functionality is already established in the monomer and does not interfere with the incorporation of incompatible functional groups like free hydroxyl, carboxyl, or amino groups.
Solution Approach 2:
The patent employs transition metal catalysts that can facilitate polymerization reactions while being compatible with multiple functional groups simultaneously. These universal catalysts enable the incorporation of various incompatible functional groups (hydroxyl, carboxyl, amino) into the polymer backbone without requiring separate protection strategies for each functional group, thereby simplifying the overall synthesis process.
3Productivity
If conventional polycondensation reactions are used, then polyacetals can be synthesized, but the method is limited and cannot accommodate functional groups incompatible with acetal formation conditions
Solution Approach 1:
The patent changes the reaction parameters and mechanism by using transition metal-catalyzed polymerization instead of conventional acid-catalyzed polycondensation. This parameter change allows the reaction to proceed under conditions that are compatible with functional groups like free hydroxyl, carboxyl, and amino groups, which would otherwise be incompatible with traditional acetal formation conditions. The transition metal catalysts enable selective bonding that preserves these functional groups while forming the polyacetal backbone.
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 enables the synthesis of polymers that can fragment upon treatment with acids or electron impact, altering physicochemical properties like solubility and melting point, and is useful in photoresist compositions without the need for costly protection strategies.
Implementation Method 1
the bis(aryl)acetals serve as the sole monomer or a comonomer in a transition metal catalyzed cross-coupling reaction (e.g., Suzuki coupling)
Implementation Method 2
Such fragmentation can be used to alter the physicochemical properties (including solubility, aggregate state, glass transition temperature, melting point, and vapor pressure) of materials or formulations comprising the oligomers or polymers
Implementation Method 3
upon treatment with Brönsted or Lewis acids or upon electron impact or ionization
Data Source
AI summary
A bis(aryl)acetal has the formulawherein Y1 and Y2 are each independently chloro, bromo, iodo, mesylate, tosylate, triflate, or Bx, provided that Y1 and Y2 are not both selected from chloro, bromo, and iodo; each occurrence of Bx is independently a boron-containing functional group bonded to Ar1 or Ar2 via a boron atom; Ar1 and Ar2 are each independently unsubstituted or substituted C6-18 arylene, or unsubstituted or substituted C3-18 heteroarylene; provided that Ar1 and Ar2 are not covalently linked to each other to form a ring structure that includes-Ar1-O—C—O-Ar2-; andR1 and R2 are each independently hydrogen, unsubstituted or substituted C1-18 linear or branched alkyl, unsubstituted or substituted C3-20 cycloalkyl, unsubstituted or substituted C6-18 aryl, or unsubstituted or substituted C3-20 heteroaryl. The bis(aryl)acetal is useful as a monomer for oligoacetal and polyacetal synthesis via Suzuki polycondensation.