Two-Step Oxidation for Furan-Dicarboxylic Acid Yield and Safety
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Solution Overview
Problem
Existing methods for producing furan-2,5-dicarboxylic acid from 5-methylfurfural result in low yields and face industrial challenges such as high oxygen concentration in off-gas, which is costly and unsafe, and the reaction yield deteriorates when oxygen concentration is lowered to suppress this.
Innovation Solution
A two-step oxidation process involving specific feeding conditions of 5-methylfurfural and an oxygen-containing gas with a lower aliphatic carboxylic acid, a bromine compound, and a metal catalyst, where the oxygen concentration and molar ratio are adjusted in each step to optimize yield and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air diluted to 8% oxygen concentration is used as oxidizing gas to suppress oxygen concentration in off-gas, then industrial safety is improved, but reaction yield deteriorates
Solution Approach 1:
The oxidation process is divided into two sequential steps with different oxygen concentration requirements. Step 1 uses highly diluted oxygen (6-12%) for safe operation, while Step 2 uses less diluted oxygen (12-21%) to achieve high conversion. This segmentation allows each step to operate under optimal conditions without compromising overall safety or yield.
Solution Approach 2:
Step 1 performs preliminary oxidation of 5-methylfurfural to intermediate products under safe oxygen concentration conditions. This preliminary action prepares the substrate for the second step, allowing the subsequent high-oxygen step to complete the oxidation to FDCA with high efficiency without safety risks.
2Reliability
If amount of air fed is lowered to suppress rise in oxygen concentration of off-gas, then industrial safety is improved, but reaction yield deteriorates
Solution Approach 1:
The air feeding is segmented into two steps with different rates. Step 1 uses lower air feeding rate (0.06-0.12 mol/min) to limit oxygen concentration rise, while Step 2 increases air feeding rate (0.12-0.21 mol/min) to enhance conversion. This temporal segmentation of feeding rates resolves the contradiction between safety and yield.
Solution Approach 2:
The air feeding rate is dynamically adjusted between two steps. The system transitions from a conservative feeding rate in Step 1 (prioritizing safety) to an aggressive feeding rate in Step 2 (prioritizing yield). This dynamic adjustment allows the process to adapt to different operational requirements at different stages.
3Reliability
If oxygen concentration in off-gas is kept low to ensure industrial safety, then safety is improved, but oxygen conversion rate must be raised which increases device complexity
Solution Approach 1:
The oxidation process is segmented into two steps, each with defined oxygen concentration ranges. Step 1 operates with 6-12% oxygen in off-gas, while Step 2 operates with 12-21%. This segmentation simplifies control by establishing clear operational boundaries for each step, reducing the complexity of maintaining low oxygen concentrations throughout the entire process.
Solution Approach 2:
The process utilizes parameter changes between two steps - oxygen concentration in off-gas, air feeding rate, and reaction conditions are adjusted according to the step. This structured parameter changes approach makes the control system more manageable compared to continuous adjustment, reducing overall device 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
The method achieves a high yield and conversion rate of furan-2,5-dicarboxylic acid while ensuring industrial safety by maintaining low oxygen concentration in off-gases and preventing side reactions.
Implementation Method 1
oxidizing a 5-substituted furfural has been carried out. Particularly, a production method involving liquid-phase oxidation with an oxygen-containing gas such as air has been developed
Implementation Method 2
in the presence of a cobalt- and manganese-based oxidation catalyst containing bromine
Data Source
AI summary
There is provided a method for producing furan-2,5-dicarboxylic acid, including: an oxidation step 1 of continuously feeding 5-methylfurfural and an oxygen-containing gas in the presence of a lower aliphatic carboxylic acid, a bromine compound and a metal catalyst to a reaction container to carry out oxidation reaction under the following feeding condition 1 or the following feeding condition 2; and an oxidation step 2, after the oxidation step 1, of continuously feeding 5-methylfurfural and an oxygen-containing gas to the reaction container to carry out oxidation reaction under such a feeding condition that the oxygen concentration of the oxygen-containing gas and/or the molar ratio of oxygen in the oxygen-containing gas to 5-methylfurfural is higher than in the oxidation step 1. The feeding condition 1 is such that the oxygen concentration of the oxygen-containing gas is 10% by volume or higher and lower than 15% by volume, and the molar ratio of oxygen in the oxygen-containing gas to 5-methylfurfural is 2.5 to 4.2; and the feeding condition 2 is such that the oxygen concentration of the oxygen-containing gas is 15 to 30% by volume, and the molar ratio of oxygen in the oxygen-containing gas to 5-methylfurfural is 1.0 or higher and lower than 2.5.