Cellulose Dissolution Process Using Ionic Liquid Solvent Exchange

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Solution Overview

Problem

Existing methods for recycling cellulose from feedstocks are inefficient, costly, and use hazardous chemicals, lacking an effective process for dissolving cellulose that is both energy-efficient and environmentally benign.

Innovation Solution

A process involving sequential use of a first solvent system, typically a cyclic amide, followed by a second solvent system comprising an ionic liquid with a stoichiometric excess of base, to dissolve cellulose at specific temperatures and times, ensuring effective and rapid dissolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional organic solvents or water are used to dissolve cellulose, then the process is environmentally benign, but cellulose dissolution does not occur due to intermolecular hydrogen bonding

Engineering Contradiction:

Improveenvironmental impactVSAvoiddissolution effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the solvent system by using ionic liquids with specific cation-anion combinations (e.g., imidazolium with acetate or chloride) that can disrupt cellulose hydrogen bonding networks. The ionic liquid structure and composition are optimized to achieve effective cellulose dissolution while maintaining environmental compatibility.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite solvent systems combining ionic liquids with other compatible solvents or additives to enhance cellulose dissolution capability. This composite approach allows the system to overcome the limitations of individual solvents while maintaining environmental benefits.

Inventive Principle:

Principle #40Composite materials

2Productivity

If Viscose process is used to produce cellulose fibres, then fibres can be produced, but highly toxic carbon disulfide is used

Engineering Contradiction:

Improvefibre production capabilityVSAvoidtoxicity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the toxic carbon disulfide reagent with ionic liquids that can be used in smaller amounts and potentially regenerated. The ionic liquid system achieves fibre production without the need for highly toxic chemicals, reducing environmental and safety concerns.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent transforms the approach by using ionic liquids that can dissolve cellulose directly without forming toxic intermediates like cellulose xanthate. This converts the harmful chemical transformation process into a benign dissolution process.

Inventive Principle:

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

3Productivity

If Lyocell process is used to dissolve cellulose, then fibres can be produced, but N-methylmorpholine N-oxide requires stabilising additives and has economic problems

Engineering Contradiction:

Improvefibre production capabilityVSAvoideconomic efficiency

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent optimizes the ionic liquid system parameters including cation type, anion type, water content, and temperature to achieve effective cellulose dissolution without requiring stabilizing additives. This simplifies the process and improves economic efficiency by eliminating additional chemical requirements.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If ionic liquids are used to dissolve cellulose, then dissolution occurs, but the process may be energy-intensive and costly

Engineering Contradiction:

Improvedissolution effectivenessVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes processing temperature and ionic liquid composition to achieve cellulose dissolution at lower energy costs. By selecting appropriate ionic liquids with lower melting points and optimized solubility parameters, the process reduces heating requirements while maintaining effective dissolution.

Inventive Principle:

Principle #35Parameter changes

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 process achieves rapid and complete dissolution of cellulose with minimal environmental impact, using non-hazardous solvents and reducing energy consumption.

Implementation Method 1

treating the wet cellulose with a second solvent system comprising an ionic liquid to dissolve the cellulose

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 2

wetting the cellulose with a first solvent system to form wet cellulose

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS12509568B2Recycling process

Publication Date: 2025.12.30 WORN AGAIN FOOTWEAR & ACCESSORIES

AI summary

The present invention provides a process for separating cellulose from a feedstock, comprising the steps of: a) wetting the cellulose with a first solvent system to form wet cellulose; b) contacting the wet cellulose with a second solvent system to form a mixture; c) maintaining the mixture at a first temperature for a first period of time; d) maintaining the mixture at a second temperature for a second period of time to dissolve the cellulose; and e) removing the first and second solvent system containing the dissolved cellulose.