FDCA Purification via Continuous Superheating Crystallization
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Solution Overview
Problem
Current methods for producing 2,5-furandicarboxylic acid (FDCA) through one-step direct oxidation of HMF result in impure and colored products due to unselective oxidation and high instability of HMF, leading to premature chain termination in polymerization reactions and poor quality polymeric materials, with existing purification techniques being inefficient due to poor solubility and high boiling point of FDCA.
Innovation Solution
A method involving superheating a mixture of undissolved FDCA and solvent in a continuous reactor at temperatures above 100°C for less than 15 minutes to dissolve and crystallize FDCA, under anaerobic conditions to minimize byproduct formation, followed by cooling to induce precipitation, effectively reducing the residence time and exposure to high temperatures to achieve higher purity and reduced color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If one-step direct oxidation of HMF is used to produce FDCA, then production efficiency is improved, but product purity and color quality deteriorate due to unselective oxidation and formation of colored byproducts
Solution Approach 1:
The patent divides the purification process into multiple sequential steps: filtration to remove catalyst, followed by selective crystallization at controlled temperatures (60-80°C), and optional activated carbon treatment. This segmented approach selectively removes colored byproducts while preserving FDCA purity, resolving the contradiction between efficient production and product quality.
Solution Approach 2:
The patent employs parameter changes by controlling crystallization temperature (60-80°C) and using activated carbon adsorption to selectively remove colored impurities. These parameter adjustments enable high-purity FDCA recovery without compromising production efficiency, addressing the quality deterioration issue.
2Manufacturing precision
If standard purification techniques such as recrystallization and distillation are used, then product purity can be improved, but process complexity and energy consumption increase due to poor solubility and high boiling point of FDCA
Solution Approach 1:
The patent simplifies the purification process by changing the temperature parameter during crystallization (60-80°C), which exploits the solubility characteristics of FDCA to achieve high purity through a single crystallization step, avoiding complex multi-step procedures and reducing energy consumption.
Solution Approach 2:
The patent introduces activated carbon as an intermediary substance that selectively adsorbs colored byproducts from the solution. This intermediary enables effective purification without requiring complex distillation or multiple crystallization cycles, reducing process complexity while maintaining high purity.
3Stability of the object's composition
If extended heating time is used to ensure complete dissolution of FDCA, then dissolution completeness is improved, but formation of colored byproducts increases due to prolonged exposure to high temperature
Solution Approach 1:
The patent applies the 'rushing through' principle by rapidly cooling the solution after brief heating, minimizing the residence time at high temperature. This approach ensures complete dissolution of FDCA while preventing prolonged thermal exposure that would generate colored byproducts, thus resolving the contradiction between dissolution completeness and byproduct formation.
Solution Approach 2:
The patent uses dynamic temperature control - heating to dissolve FDCA completely, then rapidly cooling to precipitate pure crystals. This dynamic approach ensures complete dissolution during the heating phase while the subsequent rapid cooling prevents byproduct formation, balancing dissolution completeness with minimal harmful exposure.
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 significantly increases the purity and reduces the color of FDCA crystals, achieving purity greater than 99.5% and a lighter color compared to initial crude FDCA, while minimizing downstream processing and avoiding the formation of undesirable byproducts.
Implementation Method 1
dissolving FDCA by superheating the mixture in the reactor
Implementation Method 2
superheating the mixture in the reactor; heating of the FDCA solution
Implementation Method 3
crystallizing FDCA from the mixture by cooling the mixture; cooling to induce precipitation
Implementation Method 4
crystallizing FDCA from the mixture by cooling the mixture
Implementation Method 5
crystallizing FDCA from the mixture by cooling the mixture
Data Source
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AI summary
The invention is based on the finding that when conducting crystallization of FDCA at high temperatures, the formation of significant amounts of colored byproduct can be reduced or even avoided when the FDCA mixture is kept at temperatures above 100 °C for less than 15 minutes. This is achieved by conducting the crystallization process in a continuous reactor. Accordingly, the method comprises the steps of feeding a mixture comprising undissolved FDCA and a solvent to a reactor; and dissolving FDCA by superheating the mixture in the reactor to a temperature of at least 130 °C; and crystallizing FDCA by cooling the mixture in the reactor, wherein the reactor is a continuous reactor and the residence time in the reactor zone wherein the FDCA mixture has a temperature above 100 °C is less than 15 minutes.