Ionic Liquid Solvent Control for Aromatic Carboxylic Acid Purity
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Solution Overview
Problem
Current processes for oxidizing alkyl aromatic compounds to aromatic carboxylic acids face challenges in achieving high purity due to impurities like 4-carboxybenzaldehyde and require multiple purification steps, with solvent recycling being inefficient and costly.
Innovation Solution
A process involving the use of an ionic liquid as a solvent, a bromine source, and a catalyst under oxidizing conditions to produce aromatic carboxylic acids, followed by crystallization and recycling of the mother liquor to maintain an active solvent composition, reducing impurities and operating costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional oxidation processes are used to produce aromatic carboxylic acids, then the production process can be carried out, but impurities such as 4-CBA and color bodies are generated requiring multiple purification steps
Solution Approach 1:
The patent changes the solvent parameter from conventional organic solvents to an ionic liquid system, which fundamentally alters the oxidation reaction environment. This parameter change enables selective oxidation that minimizes impurity formation, particularly 4-CBA, thereby achieving high purity products with fewer purification steps
Solution Approach 2:
The ionic liquid acts as an intermediary medium that facilitates the oxidation reaction while controlling the formation of intermediates and products. The specific ionic liquid structure mediates the reaction between alkyl aromatic compounds and oxidants, preventing the formation of harmful impurities and enabling direct production of high-purity aromatic carboxylic acids
2Manufacturing precision
If multiple purification steps are implemented to remove impurities, then the purity of the aromatic carboxylic acid increases, but the operating cost and process complexity increase
Solution Approach 1:
The patent converts the potential harm of impurity formation into a benefit by using the ionic liquid system to selectively promote the formation of desired products while inherently suppressing impurity formation. The reaction conditions in ionic liquid convert what would normally be harmful side reactions into beneficial selective oxidation pathways, eliminating the need for costly purification operations
3Productivity
If fresh solvent and catalyst are continuously added to maintain reaction efficiency, then the oxidation process continues effectively, but the operating cost increases
Solution Approach 1:
The patent implements a system where the ionic liquid solvent and catalyst are recovered and reused after the oxidation reaction. Instead of discarding these expensive materials, the process recovers them from the reaction mixture and regenerates them for continued use, thereby maintaining high reaction efficiency while minimizing material consumption and operating costs
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 approach significantly reduces impurity levels, particularly 4-CBA, and decreases the need for fresh solvent and catalyst additions, enhancing the efficiency and cost-effectiveness of the oxidation process.
Implementation Method 1
oxidation of an alkyl aromatic compound... in the presence of an ionic liquid... to produce an oxidation product comprising aromatic carboxylic acid
Implementation Method 2
cooling and filtering the material to get crude benzene di-carboxylic acid as a solid product
Data Source
AI summary
Processes have been developed for oxidizing alkyl aromatic compounds, and which reduce the amount of 4-CBA in the solid oxidation products. The process can reduce the makeup amount of ionic liquid, carboxylic acid, catalyst, bromine source, and ammonia source.