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Thiourea dioxide

CAS Number
1758-73-2
EC Number
217-168-4
Chemical Formula
CH4N2O2S
Molecular Weight
108.12 g/mol

Description

Thiourea dioxide (CAS 1758-73-2 ), also known as formamidinesulfinic acid and abbreviated as TDO, is a reductive bleaching and reducing agent used across textile, paper, and leather processing industries. It acts as a controlled source of reducing power under alkaline and elevated-temperature conditions, enabling selective bleaching and color stripping without the aggressive fiber damage associated with oxidative systems. In textile processing, TDO is used for reductive clearing after dyeing with disperse dyes on polyester, removing unfixed surface dye to improve wash fastness and color brightness. Pulp and paper producers apply it for bleaching mechanical and chemical pulps, particularly where brightness reversion needs to be minimized during the manufacturing process. Leather processors use it to achieve uniform whitening of hides prior to dyeing, ensuring consistent color uptake across the finished material and improving the final aesthetic quality. In water treatment and industrial effluent applications, it functions as a reducing agent to neutralize residual oxidants such as chlorine and chromate compounds found in waste streams. Thiourea dioxide is supplied as a white crystalline powder. Standard commercial grades include technical grade for industrial processing applications, with purity typically specified at 98% or higher. Packaging is commonly available in 25 kg bags or drums suited to bulk industrial procurement. This ensures safe handling and stability during transport and long-term storage in warehouse facilities. Contact us for supply of Thiourea dioxide Request Quote

Other Names (Synonyms)

Thiourea S,S-dioxide | Formamidinesulfinic acid | Formamidine sulfinate | Aminoiminomethanesulfinic acid | Manofast | 42BWR07L73 | Methanesulfinic acid, 1-amino-1-imino- | TDO

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point142-143 °C (decomp)
Boiling Point355.3±25.0 °C(Predicted)
Density1.68
Appearancewhite crystalline powder
ColorWhite
FormCrystalline Powder
Water Solubility30 g/L (20 ºC)
Vapor Pressure0Pa at 25℃
Refractive Index1.6550 (estimate)
pH4 (10g/l, H2O, 20℃)
Log P-3.37 at 25℃

Safety & Handling

Danger
GHS02· FlammableGHS05· CorrosiveGHS07· IrritantGHS08· Health HazardGHS06· Toxic

Hazard Statements

H251Self-heating; may catch fire
H252Self-heating in large quantities; may catch fire
H302Harmful if swallowed
H315Causes skin irritation
H318Causes serious eye damage
H319Causes serious eye irritation
H330Fatal if inhaled
H332Harmful if inhaled
H335May cause respiratory irritation
H336May cause drowsiness or dizziness
H361Suspected of damaging fertility or the unborn child
H370Causes damage to organs
H371May cause damage to organs
H373May causes damage to organs through prolonged or repeated exposure

Precautionary Statements

P203Obtain, consult and follow expert instructions for use.
P235Keep cool.
P260Do not breathe dust/fume/gas/mist/vapours/spray.
P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P264Wash … thoroughly after handling.
P270Do not eat, drink or smoke when using this product.
P271Use only outdoors or in a well-ventilated area.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P284In case of inadequate ventilation wear respiratory protection.
P316Get emergency medical help immediately.
P317Get emergency medical help.
P318IF exposed or concerned, get medical advice.
P319Get medical advice/attention if you feel unwell.
P320Specific treatment is urgent (see … on this label).
P321Specific treatment (see … on this label).
P330Rinse mouth.
P405Store locked up.
P407Maintain air gap between stacks/pallets.
P410Protect from sunlight.
P413Store bulk masses greater than … kg/… lbs at temperatures not exceeding … °C/…°F.
P420Store away from other materials.
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P317Get emergency medical help.
P352IF ON SKIN: Wash with plenty of water.
P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P316Get emergency medical help immediately.
P317Get emergency medical help.
P317If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P364Take off contaminated clothing and wash it before reuse.
P233Store in a well-ventilated place. Keep container tightly closed.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29309070
UN Number3341
ADR Class4.2
Packing GroupII
Storage Class4.2 - Pyrophoric and self-heating hazardous materials
WGK (Germany)1