What Is Ammonium Persulfate?
Ammonium persulfate is a persulfate of ammonia, also known as ammonium peroxodisulfate.
It is represented by the molecular formula (NH₄)₂S₂O₈ and has a molecular weight of 228.20 g/mol. The CAS number, which is a unique chemical number, is assigned as 7727-54-0.
Ammonium persulfate is produced by using ammonium sulfate. Specifically, ammonium persulfate is produced by supplying an ammonium sulfate solution to the anode side of an electrolytic cell separated by a cation exchange membrane.
This production method has the advantages of easy continuous operation and the ability to produce ammonium persulfate at high efficiency because there is no need to supply additional raw materials to the cathode.
At room temperature and pressure, it exists as a colorless crystal or white powder and may produce a weak, unpleasant odor. Its solubility in water is 58.2 g/100 ml at 20°C, but it is almost insoluble in ethanol and diethyl ether.
Uses of Ammonium Persulfate
Ammonium persulfate is used in a wide range of applications, primarily as an oxidative bleaching agent, metal surface treatment agent, flour modifier, polymerization initiator, and print etching agent. Potassium and sodium persulfates, as well as ammonium persulfate are sometimes used in metal surface treatment agents and oxidative bleaching agents.
When used as a flour modifier, it not only bleaches the flour itself but also provides a variety of other benefits, such as accelerating the ripening of bread. Ammonium persulfate is often used as an accelerator in the chemical polymerization process of acrylamide. When used with tetramethylethylenediamine (TEMED), enzyme radicals are induced from the persulfate, and these radicals initiate the polymerization of acrylamide.
The resulting acrylamide is used in industrial applications as a raw material for polyacrylamide, which is used in paper strengthening agents, water treatment agents, soil coagulants, leakage inhibitors, and cosmetics (shaving gel and hairdressing). Etching agents for printed circuit boards are agents that corrode metals and metal oxides, and are mainly used as a surface treatment method to shave the surface of metals, glass, and semiconductors using their own corrosive properties.
Properties of Ammonium Persulfate
Although ammonium persulfate itself does not burn, it ignites and burns violently when mixed with combustibles, so it must be handled with care. In addition, the aqueous solution itself is acidic and has been shown to be harmful to aquatic organisms.
Ammonium persulfate is a strong oxidant and reacts violently with iron, aluminum powder, and silver salts in solution. When hydrolyzed, it produces acidic ammonium sulfite and hydrogen peroxide, which exhibit strong oxidizing activity. When heated, it produces toxic and corrosive fumes (ammonia, nitrogen oxides, sulfur oxides, etc.).
Other Information on Ammonium Persulfate
Precautions for Handling and Storage
- Avoid contact with combustibles and reducing agents.
- Do not use high-temperature materials in the vicinity.
- The storage area should have fire-resistant walls, columns, and floors, and the beams should be made of noncombustible materials.
- Storage areas should be roofed with noncombustible materials, covered with metal plates or other lightweight noncombustible materials, and have no ceilings.
- Storage areas should be equipped with lighting, lighting, and ventilation facilities necessary for storage and handling.
- Store away from direct sunlight and moisture.
- Polyethylene containers are recommended for storage.
- When stored in metal containers, be aware that ammonium persulfate can be corroded by sulfuric acid produced by hydrolysis in the presence of moisture.