Thiourea dioxide

Thiourea dioxide (CAS 1758-73-2), also known as formamidinesulfinic acid and abbreviated TDO, is a reductive bleaching and reducing agent.

Where is Thiourea dioxide used?

• Textile processing: reductive clearing after dyeing with disperse dyes on polyester, removing unfixed surface dye to improve wash fastness and colour brightness
• Pulp and paper: bleaching mechanical and chemical pulps where brightness reversion must be minimised
• Leather processing: uniform whitening of hides prior to dyeing for consistent colour uptake
• Water treatment and industrial effluent: reducing agent that neutralises residual oxidants such as chlorine and chromate compounds
• Under alkaline and elevated-temperature conditions it acts as a controlled source of reducing power, enabling selective bleaching and colour stripping without the aggressive fibre damage of oxidative systems.

Commercial specifications

• Technical grade for industrial processing, purity typically 98% or higher
• 25 kg bags or drums for bulk industrial procurement