What is fuming sulfuric acid

What is fuming sulfuric acid?

Oleum, also known as "concentrated sulfuric acid", is a liquid sulfuric acid containing a large amount of sulfuric anhydride (SO) gas. It is a special form of sulfuric acid, which is highly corrosive and irritating due to its strong volatility. Oleum has important applications in industry, especially in chemical production, petroleum refining and manufacturing processes. We will learn more about the definition, properties, application of oleum and how to use it safely.

Definition and composition of oleum

oleum refers to a sulfuric acid solution containing sulfuric acid anhydride (SO) gas that is not combined with water in sulfuric acid (H₂ SO,). Generally, oleum is produced by reacting concentrated sulfuric acid with sulfuric anhydride, which contains about 10% to 20% of sulfuric anhydride (SOL3). Its appearance is colorless or slightly yellow liquid, which is highly corrosive and easily releases toxic sulfuric acid fumes in the air, so it is called "fuming sulfuric acid".

Chemical properties of oleum

since fuming sulfuric acid contains a large amount of sulfuric anhydride, it is more active than regular sulfuric acid. Its main chemical properties include:

1. strong corrosive: Fuming sulfuric acid can quickly corrode metals, wood, fabrics and other substances, and will cause serious irritation and burns to the skin and eyes after contact.
2. strong moisture absorption: It can absorb moisture in the air and quickly release sulfuric anhydride. Due to this characteristic, oleum requires special care during use to avoid contact with moisture.
3. high temperature reactivity: When fuming sulfuric acid reacts with a variety of organic and inorganic substances, it will generate a lot of heat, so special attention should be paid to temperature control during storage and use.

Application fields of fuming sulfuric acid

oleum is widely used in the chemical industry, especially in the manufacturing process. The following are some typical application areas:

1. organic synthesis: In the process of organic synthesis, oleum is often used to produce sulfate compounds. It plays an important role in the manufacture of pharmaceuticals, fragrances, plastics and dyes.
2. petroleum refining: Oleum is also widely used in the refining process of petroleum to remove impurities in the oil, especially sulfides and organic acids.
3. sulfation reaction it is used in the synthesis of other chemicals, such as the production of certain plastics, rubber and other chemical intermediates.

Safety and use precautions of fuming sulfuric acid

because oleum is highly corrosive and toxic, safety regulations must be strictly observed when using it. Here are some basic safety considerations:

1. wear personal protective equipment when operating fuming sulfuric acid, you must wear protective glasses, gloves, acid-resistant work clothes and other protective equipment to avoid skin or eye contact with liquid.
2. Avoid contact with water: Because fuming sulfuric acid will quickly release a lot of heat after contacting water, and may even cause an explosion, it is necessary to avoid contact with water or moisture.
3. Well-ventilated environment when using or storing fuming sulfuric acid, it is necessary to ensure that the operating environment is well ventilated to avoid the accumulation of sulfuric anhydride gas.

Conclusion

as an important chemical raw material, fuming sulfuric acid is widely used in organic synthesis, petroleum refining and various industrial reactions. Due to its strong corrosiveness and irritation, great care must be taken when using oleum and strict compliance with relevant safety procedures. Understanding what is oleum and its safe use can not only help us make better use of this chemical, but also effectively prevent accidents and ensure the safety of operators.