Poly(alkylene carbonate) Ether Linkage Control via Dual Catalyst System

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Solution Overview

Problem

Current methods for preparing poly(alkylene carbonate) with ether linkages have limitations, such as low catalytic activity and restricted industrial usefulness, particularly when using zinc glutarate or anilido-aldimine zinc compounds, and result in polymers with low ether linkage content.

Innovation Solution

A method involving the use of a highly-active Salen-based catalyst in combination with a double metal cyanide (DMC) catalyst for copolymerizing carbon dioxide and an epoxide compound, allowing control over the amount of ether linkages in the resulting poly(alkylene carbonate) through the ratio of catalysts and carbon dioxide pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If zinc glutarate or anilido-aldimine zinc compounds are used as catalysts for copolymerizing carbon dioxide and epoxide, then poly(alkylene carbonate) can be prepared, but the catalytic activity is low and the ether linkage content is limited

Engineering Contradiction:

Improvecatalytic activityVSAvoidether linkage content

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent combines two different catalyst systems: a Salen-based catalyst (Formula 1) and a double metal cyanide (DMC) catalyst. This merging of catalyst functions allows simultaneous promotion of carbonate linkage formation (from CO2 insertion) and ether linkage formation (from epoxide ring-opening), resolving the contradiction by achieving both high productivity and high ether linkage content in the same polymerization process

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention uses a composite catalyst system comprising both the Salen-based catalyst and the DMC catalyst working together. This composite approach leverages the complementary strengths of both catalysts to produce a copolymer with controlled and enhanced ether linkage content while maintaining high catalytic activity

Inventive Principle:

Principle #40Composite materials

2Temperature

If conventional catalysts are used to prepare poly(alkylene carbonate), then the polymer can be produced, but the glass transition temperature remains high and flexibility is insufficient for soft plastics

Engineering Contradiction:

Improveglass transition temperatureVSAvoidpolymer flexibility

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameter of the polymer by introducing ether linkages through the combined catalyst action. The ether linkages act as flexible spacers that lower the glass transition temperature and improve chain mobility, thereby enhancing flexibility without compromising manufacturability

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If poly(alkylene carbonate) is prepared without ether linkages, then the polymer structure is simple, but solubility in supercritical carbon dioxide is poor

Engineering Contradiction:

Improveether linkage contentVSAvoidsolubility in supercritical carbon dioxide

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent introduces ether linkages at specific locations within the polymer chain through the action of the DMC catalyst. These localized ether linkage structures create regions of enhanced polarity and interactability with supercritical carbon dioxide, thereby improving solubility while maintaining an otherwise simple poly(alkylene carbonate) structure

Inventive Principle:

Principle #3Local quality

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 preparation of poly(alkylene carbonate) with controlled ether linkages, enhancing the polymer's flexibility and lowering the glass transition temperature, making it suitable for soft plastics, and improving solubility in supercritical carbon dioxide.

Implementation Method 1

a method for preparing poly(alkylene carbonate) containing ether linkages, by copolymerizing an epoxide compound and carbon dioxide, with a complex of Chemical Formula 1 below and a double metal cyanide (DMC) catalyst together

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS8871898B2Method for preparing carbon dioxide/epoxide copolymers containing ether linkages

Publication Date: 2014.10.28 SK INNOVATION CO LTD

AI summary

Provided is a method for preparing poly(alkylene carbonate) containing ether linkages, by the copolymerization of an epoxy compound and carbon dioxide, with a trivalent metal complex prepared from a salen type ligand containing a quaternary ammonium salt, and a double metal cyanide (DMC) catalyst together. The amount of ether linkages can be controlled by regulating the weight ratio of two catalysts and the carbon dioxide pressure.