Sulfur dioxide

Sulfur dioxide (CAS 7446-09-5), commonly referenced as SO2 or E220, is an inorganic gas used in food processing, industrial manufacturing, and water treatment.

Where is Sulfur dioxide used?

• Food and beverage: preservative, antioxidant, and reducing agent in wines, dried fruits, and fruit juices
• Pulp and paper: bleaches cellulose fibers and neutralizes excess chlorine in effluent streams
• Mining and hydrometallurgy: reduces hexavalent chromium and precipitates metals from process liquors during ore refining
• Water treatment facilities apply it for dechlorination of potable and wastewater streams.
• Chemical intermediate in the production of sulfuric acid, sulfites, potassium and sodium hydrosulfites, and thiosulfates.
• Used in the sulfonation of oils.
• Used in oil refining, representing 4% of its use.

Good to know: Its dual role in microbial control and oxidation prevention makes it a procurement staple across multiple regulated industries.

Typical specification

• Non-volatile residue is not more than 0.05%.

Regulatory status

• Classified under CLP as a gas under pressure that may explode when heated, with hazard statement H280.
• Classified under CLP as causing severe skin burns and serious eye damage, with hazard statement H314.
• Classified under CLP as a refrigerated gas that can cause cryogenic burns or injury, with hazard statement H281.
• If sulfur dioxide or sulfite salts are present in foods, they must be labeled regardless of the type of use at a concentration of 10 mg/kg (or 10 mg/l) or more.

Storage, packaging and handling

• Contact between liquid sulfur dioxide and water may cause vigorous boiling and extremely rapid vaporization, with explosion possible if the water is hot.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.