Potassium pyrosulfite(CAS#16731-55-8)
| Hazard Symbols | Xi - Irritant |
| Risk Codes | R31 - Contact with acids liberates toxic gas R36/37/38 - Irritating to eyes, respiratory system and skin. R41 - Risk of serious damage to eyes |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. S39 - Wear eye / face protection. |
| WGK Germany | 1 |
| RTECS | TT4920000 |
| FLUKA BRAND F CODES | 23 |
| TSCA | Yes |
| HS Code | 28322000 |
| Toxicity | LD50 orally in Rabbit: 2300 mg/kg |
Introduction
It smells of sulfur dioxide. Sensitive to humidity. There is an acidic reaction. Sulfur dioxide escapes in contact with acid. It is gradually oxidized to sulfate in air and faster in humid air. If ground into powder, it can burn when it is hot. Easily soluble in water, insoluble in alcohol. Decomposition at 190 ℃. It's irritating.
Application
Potassium pyrosulfite (K₂S₂O₅, CAS 16731-55-8), also known as potassium metabisulfite or E224, is a white crystalline powder with a pungent sulfur odor, highly soluble in water and forming a slightly acidic solution. It is widely used as a preservative, antioxidant, and antimicrobial agent in the food and beverage industry. In winemaking and brewing, it releases sulfur dioxide (SO₂) to inhibit wild yeasts, bacteria, and molds, preventing oxidation, browning, and spoilage while stabilizing color and flavor. As a food additive, it extends the shelf life of fruit juices, dried fruits, seafood, potato products, jams, and canned vegetables. It also serves as a bleaching agent in coconut cream production. Beyond food applications, potassium pyrosulfite is used in water treatment to neutralize chlorine and chloramines, as a photographic fixing agent and developer preservative, in textile dyeing and cotton printing, as a reducing agent in chemical synthesis, in gold cyanidation, and as an antioxidant in pharmaceuticals. Xinchem offers custom synthesis, custom chemical synthesis, and contract manufacturing of high-purity potassium pyrosulfite with flexible scaling from R&D to commercial tons. Contact us today for a competitive quote and reliable global supply.
