Lignin-Derived Ionic Liquid Synthesis via Halogenation
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Solution Overview
Problem
Current methods for processing lignin from biorefineries and pulp and paper manufacturers primarily utilize lignin for heat generation, providing minimal economic value, and there is a need for a cost-effective and efficient route to convert lignin and hemicellulose into higher value products such as ionic liquids.
Innovation Solution
A process involving the conversion of lignin-derived aromatic starting materials through halogenation, amination, and protonation reactions using inexpensive reagents like thionyl chloride and acids to produce tertiary or quaternary ammonium salt-based ionic liquids, which can be tailored for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods using aromatic aldehydes and reagents like sodium triacetoxyborohydride are used to synthesize ammonium salt-based ILs, then the synthesis can proceed through imine formation and reductive amination, but the production cost becomes high due to expensive reagents
Solution Approach 1:
The patent replaces expensive reagents (sodium triacetoxyborohydride at ~$127/100g) with inexpensive reagents (thionyl chloride at ~$8/100g). This substitution directly addresses the cost issue by using cheaper, readily available chemicals while maintaining the synthetic pathway's effectiveness in converting aromatic aldehydes to ammonium salt-based ionic liquids.
Solution Approach 2:
The patent changes the chemical parameters of the synthesis route by switching from reductive amination conditions to a halogenation-amination-protonation sequence. This parameter change involves using different reaction conditions (halogenating agents, amines, and acids) to achieve the same transformation at lower cost, fundamentally altering the synthetic pathway's economic viability.
2Use of energy by moving object
If lignin is combusted to generate heat, steam, or electricity, then energy production is achieved, but the economic value remains minimal compared to other energy sources
Solution Approach 1:
The patent transforms lignin from a low-value combustion feedstock into a high-value chemical precursor. By changing the processing parameter from thermal combustion to chemical transformation (halogenation, amination, protonation), lignin becomes the starting material for synthesizing tailored ionic liquids, dramatically increasing its economic value while maintaining its utility as an energy-related material.
Solution Approach 2:
The patent enables lignin to serve multiple functions: it can still be used for energy generation through combustion, but now also serves as a versatile precursor for producing various ionic liquids with different applications (solvents, electrolytes, heat transfer liquids). This multi-functionality maximizes the economic value extracted from lignin resources.
3Productivity
If existing methods for converting lignin to ionic liquids are used, then some ionic liquid production is achieved, but the process requires extensive purification steps and complex synthetic routes
Solution Approach 1:
The patent segments the complex conversion process into three distinct, manageable steps: halogenation of aromatic aldehydes to form halides, amination to form amines, and protonation to form ammonium salts. This segmentation makes the overall process more controllable and easier to optimize, reducing the complexity compared to conventional one-step or less-defined methods.
Solution Approach 2:
The patent introduces intermediate compounds (halides and amines) that facilitate the transformation from aromatic aldehydes to ammonium salts. These intermediaries serve as stable, isolable species that simplify the overall synthesis by breaking down a complex transformation into simpler, well-understood reaction steps, thereby reducing process complexity.
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 reduces the production cost of ionic liquids, allows for the utilization of renewable resources, and enables the production of ionic liquids with tailored structures suitable for diverse applications, such as solvents and electrolytes, without the need for extensive purification.
Implementation Method 1
contacting a lignin-derived aromatic starting material with a halogenating agent under conditions sufficient to form a lignin-derived aromatic halide
Implementation Method 2
contacting the lignin-derived aromatic halide with an amine under conditions sufficient to form a lignin-derived aromatic amine
Implementation Method 3
contacting the lignin-derived aromatic amine with an acid under conditions sufficient to form a lignin-derived aromatic ammonium salt
Data Source
AI summary
Methods and compositions are provided for synthesizing ionic liquids from lignin. Methods and compositions are also provided for treating lignin with ionic liquids.