[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials, storage methods, industrial uses of adipic acid

Adipic acid properties

Adipic acid, chemical name adipic acid, molecular formula for C6H10O4, is an important dicarboxylic acid, room temperature for white crystalline powder or needle-like crystals. It has moderate solubility in water and can be dissolved in organic solvents such as alcohol and ether. Its melting point is 152-154°C, and its boiling point is 337.5°C. Its chemical properties are relatively stable, but it will decompose at high temperatures. Adipic acid is highly acidic and can react with alkali to form salts, and can also be esterified to form adipic acid esters. Because its molecular structure contains two carboxyl groups, it is widely used in industry.

Adipic acid use

Adipic acid has a wide range of applications in industry, the most important use is for the production of nylon 66. Nylon 66 is a synthetic fiber with excellent performance, which is widely used in textiles, automobiles, electronic appliances and other fields. Adipic acid is also used in the production of polyurethane, which reacts with polyols to produce polyurethane foam, which is widely used in furniture, construction, automobile and other industries. Adipic acid can also be used in the preparation of plasticizers, lubricating oil additives and food additives. In the pharmaceutical industry, adipic acid plays an important role in the synthesis of some pharmaceutical intermediates.

Upstream raw materials

The production of adipic acid mainly takes cyclohexane as raw material, through oxidation and nitration two-step reaction. Cyclohexane is oxidized to cyclohexanol and cyclohexanone under the action of air and catalyst, and then further oxidized to adipic acid. Benzene can also be used as the upstream raw material of adipic acid, benzene is hydrogenated to produce cyclohexane, and then through the above oxidation process to produce adipic acid. In the production process, oxidation reaction is a key step. Air oxidation or peroxide oxidation is usually used, and the reaction conditions are strictly controlled to ensure high yield and high purity.

Downstream Products

As an important organic chemical raw material, adipic acid has a wide range of downstream products. The most important downstream products are nylon 66 and polyurethane foam. Nylon 66 is widely used in textile and engineering plastics because of its high strength, high wear resistance and heat resistance. Polyurethane foam is widely used in furniture, construction, automobile and other industries, with good heat insulation, sound insulation and cushioning performance. In addition, adipic acid is also used in the production of adipic acid ester plasticizers, which are mainly used in the processing of plastics and rubber, which can effectively improve the flexibility and ductility of materials.

Production process

The production of adipic acid is mainly achieved by the oxidation reaction of cyclohexane. Cyclohexane reacts with oxygen in the air at elevated temperatures to form a mixture of cyclohexanol and cyclohexanone. Then, further oxidation produces adipic acid. The key step in the process is the control of the oxidation reaction, which needs to be carried out under suitable temperature, pressure and catalyst conditions to ensure the high efficiency of the reaction and the high purity of the product. In order to reduce the formation of by-products and improve the yield, the reaction conditions need to be optimized, such as reaction time, oxygen flow rate and so on.

storage method

Adipic acid needs to be protected from moisture and pollution during storage. Because adipic acid is easy to absorb moisture, it should be stored in a dry and cool environment to avoid contact with water. Adipic acid should be kept away from flammable and explosive materials, and the storage place should have good ventilation conditions. For large-scale storage, it is usually packaged in sealed plastic bags or steel drums to prevent moisture and contamination. During transportation, attention should be paid to prevent package damage and leakage, and to avoid violent collision and vibration.

Market Demand and Prospects

With the increasing demand of downstream industries such as nylon 66 and polyurethane foam, the market demand for adipic acid has also shown a steady upward trend. Especially in the automotive, construction and textile industries, driving the rapid growth of adipic acid demand. With the increasingly stringent environmental regulations, the demand for green production processes has also promoted the continuous innovation and improvement of adipic acid production technology. In the future, with the development of emerging applications and technological advances, the adipic acid market is expected to expand further.

Environmental Protection and Safety

Some environmental and safety problems are involved in the production and use of adipic acid. The waste gas and waste water produced in the production process need to be strictly treated to reduce environmental pollution. Adipic acid itself has a certain irritation, and it has a stimulating effect on the skin and mucous membranes. Personal protection should be done during the operation to avoid direct contact. In the process of storage and transportation, it should be operated in strict accordance with the management regulations of hazardous chemicals to ensure safety.

Conclusion

As an important organic chemical raw material, adipic acid has broad application prospects. Its stable nature and mature production process are important intermediates for the production of high-performance materials such as nylon 66 and polyurethane. With the continuous development of downstream industries and the improvement of environmental protection requirements, the market demand for adipic acid will continue to grow. In the future, through continuous improvement of production processes and development of new applications, the adipic acid industry is expected to usher in a broader space for development.