What Is Potassium Persulfate?
Potassium persulfate is a sulfur oxoacid, a type of persulfate.
It is represented by the molecular formula K₂S₂O₈ and has a molecular weight of 270.32 g/mol. It is also known as potassium peroxodisulfate. The CAS number, which is a unique chemical number, is 7727-21-1.
It is generally known to be produced by the reaction of ammonium persulfate and potassium hydroxide in an aqueous solution, a process that is still used today. At normal temperature and pressure, it exists as a white to slightly light yellowish crystal state and is odorless.
Its solubility in water is 5.2g/100ml at 20℃, but it is soluble in hot water and almost insoluble in ethanol.
Uses of Potassium Persulfate
Potassium Persulfate is mainly used in the following applications:
- Print etching agent
- Metal surface treatment agent
- Starch modifier
- Polymerization initiator for synthetic resins and fibers
- Soil conditioner
- Bleaching agent for natural products
- Synthetic oxidizers for pharmaceuticals
Etching agents for printed circuit boards are agents that corrode metals and metal oxides, and are mainly used as a surface treatment method to remove the surface of metals, glass, and semiconductors using their own corrosive properties. Etching is used not only in the manufacture of printed circuit boards but also in the processing of semiconductors and MEMS, because it can perform more precise processing in a batch than cutting or polishing.
Potassium persulfate is a powerful yet slow-reacting oxidant. It is still used today as a polymerization initiator in the synthesis of phenol, aromatic amines, and aromatic hydrocarbons. Potassium persulfate acts as an initiator in emulsion polymerization, an industrially important aqueous polymerization process.
Emulsion polymerization is a process in which insoluble monomers are mixed to form spherical micelles in a surfactant, which are then polymerized by heating with the addition of a polymerization initiator, such as potassium persulfate. This method is suitable for mass production in factories because it eliminates the heat generated during the polymerization reaction and keeps the viscosity of the system low.
Potassium persulfate is used in oxygen bleaches to bleach and clean natural products. Because it is a strong base, oxygen bleach is highly resistant to yellowing caused by grease and sebum.
Properties of Potassium Persulfate
Potassium Persulfate, when mixed with combustibles or organic materials, it decomposes by heat, impact, or friction and acts as a strong oxidizer that causes severe combustion.
When heated, it decomposes to produce sulfurous acid gas, which is gaseous sulfur dioxide. Sulfurous acid gas is a colorless, toxic gas with a pungent odor.
Inhalation of sulfurous acid gas can cause severe irritation to the respiratory system and may cause asthma. It also has the property of reacting violently with strong bases. In terms of stability, it should be prevented from exposure to high temperatures, direct sunlight, heat, and static electricity, as it may be altered by light.
Other Information on Potassium Persulfate
Handling and Storage Precautions
When handling or storing potassium persulfate, the following precautions should be taken:
- 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.
- Roofs of storage areas should be made of noncombustible materials and should not have ceilings.
- Store containers tightly closed in a cool, well ventilated, light-shielded area.