Ionic Liquid Lignin Extraction from Biomass
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Solution Overview
Problem
Current biomass pretreatment methods for lignocellulose are inefficient, as they often require high energy input, compete with food resources, and are costly due to the use of expensive ionic liquids, which fail to effectively dissolve lignin without dissolving cellulose, hindering the production of glucose and aromatic chemicals from woody plant parts.
Innovation Solution
A method involving the use of an ionic liquid composition with specific cations and anions, such as alkylammonium ions and alkyl sulfate, that selectively dissolves lignin from lignocellulosic biomass at controlled temperatures, leaving cellulose intact, thereby reducing energy requirements and enabling efficient glucose production and lignin recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional ionic liquids are used to dissolve lignin from lignocellulosic biomass, then lignin solubility is improved, but cellulose also dissolves which prevents effective separation
Solution Approach 1:
The patent applies local quality by designing ionic liquids with specific cation-anion combinations where the cation (e.g., imidazolium, pyridinium, ammonium) and anion (e.g., chloride, bromide, iodide, tetrafluoroborate, hexafluorophosphate) are selected to create localized chemical environments that selectively interact with lignin's aromatic rings and hydroxyl groups through pi-pi stacking and hydrogen bonding, while leaving cellulose's crystalline structure unaffected and undissolved
Solution Approach 2:
The patent employs parameter changes by systematically varying the cation structure (different heterocyclic rings, alkyl chain lengths), anion type (halides, tetrafluoroborate, hexafluorophosphate), temperature (50-150°C), and processing time to optimize the selective dissolution of lignin while maintaining cellulose integrity, thereby achieving precise control over separation efficiency
2Productivity
If expensive ionic liquids are used for biomass pretreatment, then lignin dissolution efficiency is improved, but production cost increases
Solution Approach 1:
The patent applies this principle by using ionic liquids in a disposable manner for the dissolution step, then removing them via evaporation or anti-solvent precipitation to recover the lignin, allowing the ionic liquid to be used once and discarded or regenerated rather than requiring long-term reuse, which reduces the need for expensive purification systems
Solution Approach 2:
The patent reduces cost by optimizing parameters such as using smaller alkyl chains (methyl, ethyl, propyl) instead of larger bulky groups, selecting cheaper anions like chloride or bromide over expensive perfluorinated anions, and finding the minimum effective concentration and processing time to achieve sufficient lignin dissolution without excessive ionic liquid consumption
3Speed
If high energy input is applied to dissolve lignin, then dissolution rate is improved, but energy consumption increases
Solution Approach 1:
The patent optimizes the balance between temperature and time by conducting dissolution at moderate temperatures (50-150°C) for extended periods (1-24 hours), or at higher temperatures (150-200°C) for shorter times (0.5-2 hours), thereby achieving effective lignin dissolution without excessive energy input, and by selecting ionic liquids with appropriate melting points and viscosities for the operating conditions
Solution Approach 2:
The patent uses composite ionic liquid systems combining different cation-anion pairs or mixing multiple ionic liquids to enhance lignin dissolution efficiency at lower temperatures and shorter times, thereby reducing energy consumption while maintaining high dissolution rates through synergistic interactions between different ionic liquid components
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 improves saccharification yields by selectively dissolving lignin, reducing energy needs, and allowing for the efficient production of glucose and lignin-based biochemicals, while being cost-effective due to the use of cheaper alkyl amine-derived ionic liquids.
Implementation Method 1
contacting the lignocellulose biomass with a composition comprising an ionic liquid to produce a cellulose pulp, wherein the ionic liquid comprises (i) a cation of Formula I... and (ii) an anion or a mixture thereof selected from C1-20 alkyl sulfate [Alkyl SO4]-, C1-20 alkyl sulfonate [Alkyl SO3]-, hydrogen sulfate [HSO4]-, hydrogen sulfite [HSO3]-, dihydrogen phosphate [H2PO4]-, hydrogen phosphate [HPO4]- and acetate [MeCO2]-
Data Source
AI summary
The present invention relates to an improved method for treating a lignocellulose biomass in order to dissolve the lignin therein, while the cellulose does not dissolve. The cellulose pulp obtained can be used to produce glucose. In addition the lignin can be isolated for subsequent use in the renewable chemical industry as a source for aromatic platform chemicals.