Biotech-Derived Dicarboxylic Acid Purification by Nitric Acid Oxidation
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Solution Overview
Problem
Existing biotechnological processes for producing saturated linear aliphatic dicarboxylic acids from renewable sources result in products with insufficient purity due to chromophoric and volatile substances, limiting their use in critical applications like textile-grade polyamides, and existing purification methods are inefficient or costly.
Innovation Solution
A process involving the use of nitric acid oxidation followed by activated carbon bleaching to chemically degrade impurities and achieve high purity, including steps of pH adjustment, dissolution in nitric acid, recovery, redissolution with activated carbon, and final crystallization to obtain high-purity dicarboxylic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If biotechnological processes are used to produce dicarboxylic acids from renewable sources, then environmental sustainability is improved, but product purity deteriorates due to chromophoric and volatile substances
Solution Approach 1:
The patent employs nitric acid as a strong oxidizing agent to chemically degrade chromophoric and volatile impurities in biotechnologically produced dicarboxylic acids. The oxidation process converts colored compounds and organic contaminants into colorless, volatile products that can be removed by filtration and evaporation, thereby restoring product purity while maintaining the green chemistry advantage of using renewable feedstocks
Solution Approach 2:
The patent uses activated carbon adsorption to selectively remove chromophoric substances and volatile impurities from the dicarboxylic acid solution. The activated carbon acts as an adsorbent that extracts colored contaminants from the solution through adsorption, allowing the purified dicarboxylic acid to be recovered in high purity form suitable for textile-grade polyamide production
2Quantity of substance
If traditional purification methods are used on biotechnological products, then product recovery is achieved, but purification efficiency deteriorates due to complex impurity profiles
Solution Approach 1:
The patent optimizes purification parameters including nitric acid concentration (6-12 M), oxidation temperature (60-100°C), and treatment time (1-4 hours) to maximize impurity degradation while preserving dicarboxylic acid integrity. These parameter adjustments enable efficient differentiation between impurities that need removal and the target product that must be retained, significantly improving purification efficiency compared to conventional methods
3Manufacturing precision
If multiple purification steps are implemented to achieve high purity, then product quality is improved, but process complexity increases
Solution Approach 1:
The patent combines oxidation and adsorption purification steps into an integrated process sequence that achieves fiber-grade purity (APHA color <15, absorbance <300 at 275 nm). The method merges chemical oxidation with physical adsorption in a coordinated manner, where nitric acid oxidation degrades chromophoric compounds and activated carbon adsorption removes remaining impurities, achieving high product quality through a streamlined multi-step process rather than numerous separate operations
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 process achieves dicarboxylic acids with optical properties comparable to fossil-derived products, suitable for textile-grade polyamides, with APHA color <15 and absorbance <300 at 275 nm, overcoming the limitations of previous methods.
Implementation Method 1
dissolution of the crude mixture obtained in step b) containing one or more saturated linear aliphatic dicarboxylic acids and impurities in an oxidizing solution of nitric acid
Implementation Method 2
redissolution of saturated linear aliphatic dicarboxylic acids in an aqueous mixture comprising activated carbon
Implementation Method 3
final crystallization to obtain high-purity dicarboxylic acids
Data Source
AI summary
A process for the purification of saturated linear aliphatic dicarboxylic acids, or mixtures thereof, obtained by biotechnological processes is described.