Sulfur Dioxide

Synonyms: E220; sulfur(IV) oxide; sulfurous anhydride; sulfurous oxide.

Description: Sulfur dioxide occurs as a colorless gas at room temperature and pressure, with a strong, suffocating, pungent odor. It is noncombustible and is a strong reducing agent.

Chemical Name: Sulfur dioxide

Antimicrobial preservative; antioxidant.

• Sulfur dioxide is used as an antioxidant for pharmaceutical injections.

• It is also used as a preservative and antioxidant in the food and cosmetics industries.

Sulfur dioxide reacts vigorously with strong alkalis and oxidizing agents. The moist gas corrodes most metals. Sulfur dioxide is incompatible with chlorates, fluorine, interhalogens, powdered metals, metal oxides, metal acetylides, sodium hydroxide, and diethyl zinc. It is also incompatible with thiamine and gelatin. See further details under Sodium metabisulfite.

Sulfur dioxide is used in food and pharmaceutical products. However, in large amounts, sulfur dioxide gas is highly irritant to the eyes, skin, and mucous membranes. Inhalation can lead to severe irritation of the respiratory tract. Direct contact with the liquid form may cause frostbite. Sulfur dioxide and sulfites may also cause allergic reactions and asthma.

Observe normal precautions appropriate to the circumstances and quantity of the material handled. Sulfur dioxide forms sulfurous acid on contact with water. When heated to decomposition, it emits toxic fumes of sulfur oxide gases. Avoid inhalation and contact with eyes and skin.

Potassium metabisulfite; sodium metabisulfite; sodium sulfite.