Potassium Metabisulfite
Dipotassium Disulfite
- CAS
- 16731-55-8
- EC
- 240-795-3
- Food Code
- E224
- Sectors
- Food & Nutrition, Textiles, Leather & Paper, Water & Wastewater Treatment
Potassium Metabisulfite (CAS 16731-55-8) is an inorganic sulfite salt that appears as a white to slightly yellowish crystalline powder, releases sulfur dioxide when dissolved in water, and acts as an antioxidant and antimicrobial preservative in food processing, textile dyeing and water treatment. It has a sulfurous odor and is stable under dry conditions but decomposes in acidic media for controlled release applications.
Typical Properties
| Molecular formula | H2O5S2.2K |
|---|---|
| Molecular weight | 222.32 g/mol |
| Appearance | White to slightly yellowish fine cryst. powder |
| Form | Powder/Solid |
| Color | White to slightly yellow |
| Odor | Odorless |
| Melting point | 150 °C (decomp) |
| Density | 2.3 g/cm³ |
| Water solubility | Soluble in water. Insoluble in ethanol. |
| pH | 2.5-4.5 (25°C, 0.1M in H2O) |
| GHS signal word | Danger · Corrosive, Irritant / harmful |
| HS code | 28322000 |
| Grades available | Food Grade |
Typical literature values for identification; lot-specific results are stated on the certificate of analysis (COA) and the safety data sheet (SDS) that accompany every delivery.
Potassium Metabisulfite
Applications
Key in winemaking for sterilization and oxidation prevention; in pharmaceutical stabilizers for injectables; in textile dyes for color fixation; in food processing for fruit preservation; and in water treatment for chlorine neutralization in large-scale systems.
Safety & Risks
Releases irritating SO2 vapors triggering asthma attacks; corrosive to skin in wet forms. Acid interactions produce toxic gases; equip workspaces with gas detectors and respiratory protection, following strict exposure limits.
Packaging
Contained in 25 kg multi-ply polyethylene bags with valve closures for easy dispensing. Ventilate storage silos, keeping distant from acidic inventories.