Tetramethylthiuram

Tetramethylthiuram refers to a subset of thiuram compounds derived from thiourea by forming a disulfide linkage between two dimethylthiourea units. The most widely encountered derivative is tetramethylthiuram disulfide, commonly known as thiram or TMTD. Its structure consists of two N,N-dimethylthiourea units joined by a sulfide disulfide bond: (CH3)2N-C(=S)-S-S-C(=S)-N(CH3)2.

Production and properties: Tetramethylthiuram disulfide is typically prepared by oxidation of the corresponding dithiocarbamate derived from dimethylamine and carbon disulfide. It is a crystalline solid at room temperature and is soluble in many organic solvents; it can decompose upon heating. It is generally stored under conditions that limit exposure to light and heat to maintain stability.

Uses: It is used as a fungicide and seed treatment to control fungal diseases, and as a vulcanization accelerator in natural and synthetic rubbers, where it speeds the curing process. It is also employed as an additive in some adhesives and coatings.

Safety and regulation: Tetramethylthiuram compounds can be irritants and skin sensitizers; exposure may cause dermatitis in sensitive individuals. Inhalation or ingestion can lead to adverse health effects. Because of toxicity to non-target organisms, the compound is subject to regulatory controls under pesticide and chemical safety laws in many jurisdictions, with handling and application typically restricted to trained personnel.

See also: Thiram; Thiuram; Thiuram disulfides.