Protic Ionic Salt Catalyzed Polyether Synthesis

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Solution Overview

Problem

Current methods for synthesizing polyethers, such as ring-opening polymerization and acid-catalyzed condensation, face limitations in producing larger polyethers efficiently due to stability issues and by-product formation, and require large amounts of ionic liquids that act as both catalysts and solvents.

Innovation Solution

The use of protic ionic salts formed by combining a Brønsted acid and a Brønsted base as catalysts in direct diol polymerization allows for the synthesis of polyethers under mild conditions, reducing the need for excessive solvent and enabling the production of polyethers with a higher number of methylene units without generating harmful by-products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ring-opening polymerization of cyclic ethers is used, then polyepoxides, polyoxetanes, and polytetrahydrofurans can be prepared efficiently, but larger polyethers (containing 6 or more methylene units) cannot be obtained due to extreme stability of the cyclic ether precursors

Engineering Contradiction:

Improvepolyether synthesis efficiencyVSAvoidpolyether chain length range

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention changes the fundamental reaction parameters by switching from ring-opening polymerization to direct condensation polymerization of diols. This parameter change enables the synthesis of polyethers with 6 or more methylene units that cannot be obtained through conventional ring-opening methods, thus expanding the adaptable chain length range while maintaining synthesis efficiency.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If Williamson synthesis is used to produce polyethers with larger number of methylenes, then the ether bond can be generated efficiently through SN2 mechanism, but polymerization generates by-products such as choline which limits industrial implementation

Engineering Contradiction:

Improvepolyether synthesis rateVSAvoidby-product formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention eliminates the harmful by-product formation issue by completely changing the reaction mechanism from Williamson synthesis (SN2) to direct condensation polymerization. This converts the harmful effect of choline by-products into a beneficial clean reaction process that produces only water as a by-product, enabling industrial implementation while maintaining high productivity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention changes the reaction type parameter from substitution (SN2) to condensation polymerization, fundamentally altering the by-product profile from choline to water, thus eliminating the harmful effects while preserving efficient ether bond formation.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If acid-catalyzed condensation between two alcohols is used, then polyethers can be synthesized, but the reaction requires high temperature (300° C.) and strong acid conditions which cause ether breakdown and acid volatility

Engineering Contradiction:

Improvepolyether synthesis capabilityVSAvoidreaction temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The invention changes the temperature parameter from 300°C to a mild range of 60-150°C, and changes the catalyst from strong mineral acids to protic ionic salts. This parameter change enables the same condensation polymerization reaction to proceed under mild conditions, preventing ether breakdown and acid volatility while maintaining synthesis capability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces expensive and hazardous strong acids with cheaper and safer protic ionic salts that can be easily handled and do not require special safety measures, making the process more industrially viable while maintaining effectiveness.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If ionic liquids of Brønsted acids are used as reaction medium and catalyst, then the catalytic activity is combined with high thermal stability and low vapor pressure, but large amounts of ionic liquids are required which act as both catalyst and solvent

Engineering Contradiction:

Improvethermal stability and vapor pressure propertiesVSAvoidamount of ionic liquid required

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention extracts the essential catalytic function from ionic liquids, using only the protic ionic salt as catalyst without requiring the bulk ionic liquid as solvent. This separates the catalytic activity from the solvent function, reducing the amount of ionic liquid from large quantities to small catalytic amounts, thus lowering cost and simplifying the process while maintaining thermal stability benefits.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method achieves high yields and purities of polyethers, simplifies the synthesis process, and reduces raw material costs by using protic ionic salts as catalysts, enabling the production of polyethers with a range of molecular weights and structures, including those with 6 or more methylene units.

Implementation Method 1

Another way to produce polyethers consists of acid-catalyzed condensation between two alcohols

Methodology Applied

Scientific EffectCondensation reaction:

Implementation Method 2

In the presence of a protic ionic salt formed by the combination of a Brønsted acid and a Brønsted base as catalysts

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

protic ionic salts formed by the combination of a Brønsted acid and a Brønsted base

Methodology Applied

Scientific EffectProton transfer:

Data Source

PatentUS12104015B2Method for the synthesis of polyethers

Publication Date: 2024.10.01 BASQUE CENT FOR MACROMOLECULAR DESIGN & ENG POLYMAT FUNDAZIOA

AI summary

A method for the preparation of polyethers is provided, the method using a protic ionic salt formed by the combination of a Bronsted acid and a Bronsted base, as well as to the polyethers obtained using the method.