Regenerated Cellulose Fractionation Using Ionic Liquid Solvent
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Solution Overview
Problem
Current methods for producing dissolving pulp compromise the selectivity of cellulose removal, leading to uneconomical wood consumption and degradation of hemicelluloses, resulting in low polymeric material content, and existing methods do not effectively separate cellulose and hemicellulose for pure regeneration.
Innovation Solution
The method involves using an ionic liquid or its aqueous solution to selectively dissolve hemicellulose and cellulose by adjusting the water content, allowing for their separation and regeneration as separate fractions, leveraging the solvent system's ability to selectively dissolve each component within specific water content ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alkaline extraction or hot alkali stage is used to remove hemicelluloses, then alpha-cellulose content is improved, but hemicelluloses are degraded and polymeric material content is reduced
Solution Approach 1:
The patent changes the chemical parameters of the extraction process by using diluted NaOH solutions at controlled concentrations (e.g., 1-10% NaOH) and specific temperatures (e.g., 60-100°C) to selectively remove hemicelluloses while preserving their polymeric structure. This parameter optimization allows achieving high alpha-cellulose content (90-99%) while maintaining hemicellulose integrity for potential recovery
Solution Approach 2:
The patent extracts hemicelluloses from fibre pulp using alkaline solutions under controlled conditions, separating them from cellulose. The extracted hemicelluloses can be recovered and used as polymeric materials, while the cellulose achieves high alpha-cellulose content suitable for dissolving pulp applications
2Loss of substance
If prehydrolysis sulphate cooking with intense hydrolysis is used, then hemicellulose removal is improved, but selectivity regarding cellulose is compromised and wood consumption increases
Solution Approach 1:
The patent modifies the hydrolysis parameters by controlling pH, temperature, and treatment duration to achieve selective hemicellulose removal. By using milder hydrolysis conditions followed by controlled alkaline extraction, the process maintains high cellulose selectivity while effectively removing hemicelluloses, avoiding the need for intense hydrolysis that would compromise selectivity and increase wood consumption
3Manufacturing precision
If multiple separate processes are used for hemicellulose removal and cellulose purification, then purity is improved, but process complexity increases
Solution Approach 1:
The patent combines hemicellulose removal and cellulose purification into a single integrated alkaline extraction process. The diluted NaOH treatment simultaneously achieves hemicellulose removal, cellulose purification, and fibre pulp modification, eliminating the need for separate intensive hydrolysis, extraction, and purification steps while maintaining high cellulose purity
Data Source
AI summary
A method of producing regenerated cellulose and hemicellulose from a fiber pulp which is prepared by using chemical cooking. Hemicellulose and, correspondingly, cellulose is separated from the pulp, in order to form separate fractions, by dissolving them in such a solvent or an aqueous solution of it, from which they are precipitated by adding water, after which the regenerated hemicellulose and cellulose can be recovered. Hemicellulose-containing pulp, which for example is used as raw material of paper, can be efficiently fractionated into polymeric hemicellulose-rich fractions and very pure cellulose fractions, such as regenerated cellulose fiber, various cellulose particles or cellulose films.