Thiurams

Thiurams are a family of organosulfur compounds derived from dithiocarbamates, characterized by a disulfide linkage joining two dithiocarbamate units. The best-known member is tetramethylthiuram disulfide (TMTD). These compounds are produced in a way that allows various alkyl or aryl groups to be attached to the amine-derived portions, giving a range of thiuram derivatives.

Chemically, thiurams consist of two dithiocarbamate groups connected by a disulfide bond. They are typically prepared by oxidation of dialkyl dithiocarbamates, which are in turn formed by the reaction of secondary amines with carbon disulfide. The resulting disulfide structure is central to their properties as accelerators and reagents in industrial chemistry.

Uses of thiurams are diverse. In the rubber industry, they function as accelerators that speed vulcanization, improving the elasticity, strength, and durability of rubber products. They are also used in agriculture as fungicides and pesticides, with thiram (tetramethylthiuram disulfide) among the well-known examples. Some thiurams find applications as stabilizers or processing aids in certain polymers.

Health and safety considerations are important for thiurams. They are known skin sensitizers and can cause allergic contact dermatitis upon exposure, making occupational safety a key concern in rubber and plastics manufacturing. Patch testing for contact dermatitis commonly includes a thiuram mix to identify sensitivity. They may irritate eyes and the respiratory tract in some individuals. Environmentally, thiuram compounds can be toxic to aquatic life; their persistence is countered by hydrolysis and biodegradation under appropriate conditions.

See also: Thiram, Tetramethylthiuram disulfide, Thiuram mix.