[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials, storage methods of aromatic compounds, definition of aromatic compounds Senior high school chemistry

Properties of aromatic compounds

Aromatic compounds (Aromatic Compounds) refer to those organic compounds having an aromatic or benzene-like ring structure. Its most notable feature is the inclusion of one or more benzene rings, which are cyclic structures formed by six carbon atoms through alternating double and single bonds. This structure gives the aromatic compounds some unique chemical properties, such as a highly stable conjugated system, low reactivity, and characteristic aroma. The electron cloud distribution of the benzene ring makes these compounds have a high degree of chemical stability, and it is difficult to undergo addition reactions, but it is easy to undergo substitution reactions.

Main Uses of Aromatic Compounds

aromatic compounds play an important role in the chemical industry and are widely used in various fields. The most common uses include:

1. solvent aromatic compounds such as benzene, toluene and xylene are commonly used as organic solvents and are widely used in coatings, adhesives and cleaning agents.
2. chemical raw materials aromatic compounds are the basis of many important chemicals, such as plastics, synthetic fibers, rubber and dyes. Benzene can be used to produce styrene, phenol, cyclohexane and other compounds.
3. Medicine many drugs such as aspirin and paracetamol contain aromatic structures, and the presence of benzene rings helps to improve the stability and activity of drugs.
4. Pesticides many pesticides such as herbicides and insecticides also contain aromatic structures to improve their effectiveness and stability.

Upstream raw materials

aromatic compounds are produced from a range of upstream feedstocks, typically from petroleum and coal chemicals. The main upstream feedstocks include:

1. oil petroleum cracking is one of the important methods to obtain aromatic compounds, and basic aromatic compounds such as benzene, toluene and xylene can be obtained from petroleum through catalytic reforming, cracking and other processes.
2. coal tar coal tar is another important source of aromatic compounds, especially in the coal chemical industry, various aromatic compounds can be extracted from coal tar by distillation and rectification.
3. Natural gas: Through the methane aromatization reaction, the methane in natural gas can be converted into benzene and other aromatic compounds.

Downstream Products

as basic chemical raw materials, aromatic compounds can be further processed to produce a variety of downstream products, which have a wide range of applications in industry and daily life:

1. plastic: Styrene monomer can be polymerized into polystyrene, which is a plastic widely used in packaging materials, disposable tableware and home appliance shells.
2. synthetic fiber: Paraxylene is an important raw material for the production of polyester fibers, which are widely used in the textile and apparel industries.
3. Rubber: Benzene can be used to produce synthetic rubber, such as styrene-butadiene rubber, which has excellent wear resistance and elasticity and is widely used in tires and industrial products.
4. Dyes and Pigments: Many dyes and pigments contain aromatic structures, such as aniline black and azo dyes. These compounds can provide rich colors and excellent light resistance.

Storage Methods of Aromatic Compounds

aromatic compounds are usually volatile and toxic, so special attention should be paid to the following points when storing:

1. sealed container: Due to their volatility, aromatic compounds should be stored in a well-sealed container to prevent leakage and evaporation.
2. a well-ventilated warehouse: The warehouse storing aromatic compounds should have good ventilation conditions to avoid the accumulation of harmful gases and ensure air circulation.
3. Keep away from fire source: Many aromatic compounds are flammable, so the storage area should be away from fire and heat sources, and equipped with appropriate fire extinguishing equipment.
4. low temperature storage: Some aromatic compounds are more stable at low temperatures, so they are suitable for storage in a cool, dry environment, away from direct sunlight.

Environmental and health impacts

although aromatic compounds are widely used in industry, they also have potential hazards to the environment and human health. Benzene and some polycyclic aromatic hydrocarbons (PAHs) are considered carcinogens, and long-term exposure can cause serious health problems. Therefore, in the process of production and use, it is necessary to strictly control its emission and exposure, and adopt effective protective measures and environmental protection technology.

Conclusion

aromatic compounds have become an important part of the chemical industry because of their unique chemical properties and a wide range of industrial applications. Understanding its nature, use, upstream and downstream raw materials and storage methods will not only help its effective use, but also reduce the harm to the environment and human health. In the future, with the advancement of technology and the improvement of environmental awareness, the production and application of aromatic compounds will develop in a safer, greener and more efficient direction.