Halogen Metal Ionic Liquid Catalyzed Lignin Depolymerization
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Solution Overview
Problem
Current methods for lignin depolymerization to produce p-hydroxycinnamate suffer from poor selectivity and low efficiency, complex product components, high energy consumption, and difficulty in catalyst recovery, limiting the effective utilization of agricultural and forestry wastes.
Innovation Solution
A method using a halogen metal-based ionic liquid as a catalyst for selective catalytic lignin depolymerization, involving the preparation of an ionic liquid from metal chloride and imidazole chloride, and subsequent reaction with herbaceous lignin in the presence of a C1-C4 fatty alcohol solvent to achieve high selectivity and product separation, with the option for catalyst recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used for lignin depolymerization, then the process is simple, but the selectivity is poor and product components are complex
Solution Approach 1:
The patent uses ionic liquids as intermediary substances to mediate the depolymerization reaction of lignin. The ionic liquid catalyst selectively facilitates the breaking of specific bonds in lignin structure, enabling high selectivity for p-hydroxycinnamate production while maintaining a relatively simple process framework.
Solution Approach 2:
The patent employs ionic liquids with adjustable chemical composition and physical properties as catalysts. By changing parameters such as cation type, anion type, and structural modifiers in the ionic liquid, the selectivity and activity can be optimized for specific depolymerization pathways, achieving high selectivity without complex process conditions.
2Productivity
If conventional catalytic methods are used, then the reaction can proceed, but the energy consumption is high and efficiency is low
Solution Approach 1:
The patent replaces conventional high-energy mechanical or thermal processing methods with ionic liquid-catalyzed chemical reactions. The ionic liquid catalyst lowers the activation energy barrier, enabling depolymerization to proceed under milder conditions with lower energy input while maintaining high reaction efficiency.
Solution Approach 2:
By using ionic liquids with tunable properties, the reaction conditions can be optimized to achieve high productivity at lower temperatures and pressures compared to conventional methods, thereby reducing energy consumption while improving reaction efficiency.
3Ease of manufacture
If conventional catalysts are used, then the reaction can be catalyzed, but the catalyst recovery is difficult
Solution Approach 1:
The patent employs ionic liquids as recoverable catalysts that can be separated from the reaction mixture and reused. The unique properties of ionic liquids allow for easy recovery through methods such as extraction or filtration, minimizing catalyst loss and enabling multiple cycles of use, thus improving ease of manufacture.
4Productivity
If traditional synthesis methods are used for p-hydroxycinnamate, then the process is established, but the yield is low and the process is tedious
Solution Approach 1:
The patent extracts or isolates p-hydroxycinnamate directly from lignin depolymerization using ionic liquid catalysts, bypassing multiple traditional synthesis steps. This direct conversion approach simplifies the process by removing unnecessary intermediate steps while achieving high yield through selective catalysis.
Solution Approach 2:
By using ionic liquids with optimized chemical parameters, the depolymerization reaction achieves high selectivity and yield for p-hydroxycinnamate in a single step, replacing the multi-step traditional synthesis process and reducing overall 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 achieves a 40-50% reaction conversion and 55-75% selectivity for p-hydroxycinnamate production, with the halogen metal-based ionic liquid offering simple preparation, low cost, and reusability, while maintaining the structural integrity of the regenerated lignin for further processing.
Implementation Method 1
uses a metal-base ionic liquid synthesized from metal chloride and imidazole chloride as a catalyst, with the ionic liquid having low cost and economical synthesis process
Implementation Method 2
uses C1-C4 fatty alcohol as a solvent, which not only makes the product p-hydroxycinnamate have higher selectivity, but also can realize product separation and catalyst recycling
Data Source
AI summary
The present invention discloses a method for preparing p-hydroxycinnamate by using an ionic liquid for catalytic lignin depolymerization comprising: 1) preparation of a halogen metal-based ionic liquid: preparing the halogen metal-based ionic liquid by reacting an alkylimidazole chloride with a metal chloride by heating the same to 30° C. to 80° C. with stirring; and 2) catalytic depolymerization of lignin: mixing the halogen metal-based ionic liquid and lignin with an alcohol, and after N2 replacement, heating the solution to 140° C. to 200° C. and reacting the solution for 4-8 h while stirring to prepare high value-added chemicals with p-hydroxycinnamate as a main product. The present invention has advantages of a simple process, mild conditions, environmental kindness, and high selectivity for a main product. The ionic liquid is simple in preparation, has a good atom economy, and is recyclable. Under optimal conditions, the yield of p-hydroxycinnamate can reach 40-80 mg/g.