1. Question: What is adipic acid? What is its chemical formula?
Answer:
Adipic acid is an important organic dibasic carboxylic acid, with the chemical formula HOOC(CH2)4COOH (or simply written as C6H10O4). It appears as a white crystalline powder, is slightly soluble in water, and has a mild sour taste.
2. Question: What are the main uses of adipic acid?
Answer:
The core use is in the production of nylon (polyamide):
Approximately 70% of adipic acid is used to manufacture nylon 66 (produced by polycondensation with hexamethylenediamine).
Other uses include:
As a raw material for polyurethane (PU) foam;
As a plasticizer (such as dioctyl adipate in PVC);
In the food industry (as an acidulant, with E number E355);
As a pH regulator in cosmetics and pharmaceuticals.
3. Question: How is adipic acid produced industrially?
Answer:
The mainstream process is the cyclohexanone/cyclohexanol oxidation method (KA oil method):
Benzene → cyclohexane (by hydrogenation) → a mixture of cyclohexanone and cyclohexanol (KA oil);
KA oil is oxidized to adipic acid under the catalysis of nitric acid.
Environment - friendly alternative method:
The biological method (such as microbial fermentation of glucose) is under development to reduce the emission of N2O (a strong greenhouse gas) from traditional processes.
4. Question: What are the physical properties of adipic acid?
Answer:
Melting point: 153°C (the high melting point is beneficial for crystallization treatment);
Solubility: Slightly soluble in cold water (1.5g/100mL, 20°C), easily soluble in hot water, ethanol, and acetone;
Acidity: pKa1≈4.43, pKa2≈5.41 (typical properties of a weak acid);
Crystal structure: Monoclinic system, with the molecular chain arranged in a zig - zag pattern.
5. Question: What are the challenges and progress of adipic acid in the environmental protection field?
Answer:
Challenges: The traditional nitric acid oxidation method produces a large amount of N2O (with a greenhouse effect 265 times that of CO2);
Solutions:
Catalytic decomposition: Convert N2O into N2Oand O2;
Biological method: Use engineered strains (such as Escherichia coli) to directly ferment sugars to synthesize adipic acid;
Green oxidants: Research the use of H2O2 or ozone instead of nitric acid.
Audited Supplier 
){kind=link}