Adipic Acid Synthesis via Nitric Oxide Mediated Oxidation
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Solution Overview
Problem
Conventional processes for producing adipic acid using nitric acid and oxidation catalysts face challenges such as high costs, the need for catalyst recycling, poor selectivity, and the formation of impurities like glutaric and succinic acids, along with difficulties in controlling nitrous vapor generation.
Innovation Solution
A process that uses nitric acid in the presence of significant nitrogen oxides concentrations, eliminating the need for catalysts and allowing for high selectivity and yield of adipic acid without intermediate separation, while also enabling the recycling or consumption of nitrogen oxides, and can be conducted at lower temperatures and in a continuous or discontinuous manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxidation catalysts (copper and vanadium) are used in the nitric acid oxidation process, then the oxidation reaction can proceed, but the process becomes complex requiring catalyst recycling and additional purification stages, increasing cost and device complexity
Solution Approach 1:
The invention extracts and eliminates the catalyst components (copper and vanadium) from the oxidation system, replacing them with an organic peroxide-based oxidation mechanism. This removes the need for catalyst recycling and associated purification stages, directly reducing device complexity while maintaining oxidation efficiency
Solution Approach 2:
The invention replaces expensive, reusable metal catalysts with a disposable organic peroxide oxidant system. The organic peroxide is consumed in the reaction rather than recycled, eliminating the complex infrastructure needed for catalyst recovery and purification, thereby simplifying the overall process
2Device complexity
If conventional nitric acid oxidation is used without catalysts, then catalyst costs and recycling complexity are reduced, but selectivity for adipic acid decreases due to formation of other diacids (glutaric and succinic acids)
Solution Approach 1:
The invention changes the chemical parameters of the oxidation system by introducing organic peroxides with specific oxidation potentials and reaction kinetics. This parameter change enables high selectivity for adipic acid without requiring metal catalysts, achieving both process simplicity and manufacturing precision
3Manufacturing precision
If high purity adipic acid (>99%) is required for textile, electronics, or food industries, then additional purification stages must be implemented, but this increases production time and cost
Solution Approach 1:
The invention performs preliminary action by designing an oxidation system that produces adipic acid with inherently high purity (>99%) from the start. The organic peroxide-based oxidation selectively forms adipic acid with minimal by-products, eliminating the need for subsequent purification stages and reducing production time
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 process achieves adipic acid selectivity greater than 90% and high yields, reduces residual metal content, and is more environmentally friendly by avoiding catalyst-related costs and processes, with the ability to operate effectively with various substrates and at lower temperatures.
Implementation Method 1
adipic acid is conventionally synthesized by oxidation with nitric acid of a mixture of cyclohexanone and cyclohexanol
Implementation Method 2
nitric oxidation by nitric acid or by nitrogen oxides of compounds such as cyclohexanol generates nitrous vapors
Data Source
AI summary
The present invention relates to a process for preparing dicarboxylic acids, in particular adipic acid (1,6-hexanedioic acid), through the action of nitric acid, from cyclic alcohols or ketones with a corresponding number of carbon atoms, in the presence of one or more nitrogen oxides in a molar concentration in the reaction medium of greater than 2.5 mmol per kg of reaction medium.