Tetrakis(hydroxymethyl)phosphonium sulfate
Description
Tetrakis(hydroxymethyl)phosphonium sulfate (CAS 55566-30-8), commonly known as THPS, is a water-soluble organophosphorus biocide and flame retardant used across industrial and specialty chemical markets.
Supplied under trade names such as Retardol S and Pyroset TKO, it delivers broad-spectrum antimicrobial activity alongside durable flame retardancy in treated substrates for various sectors.
In water treatment, THPS controls sulfate-reducing bacteria and biofilm formation in oilfield injection systems, cooling towers, and industrial process water systems to maintain operational efficiency.
Textile and nonwoven manufacturers apply it as a durable flame retardant finish for cotton and cellulosic fabrics, where it bonds to fiber during curing to meet fire performance standards.
In leather processing, it functions as a biocide during hide preservation and wet-end operations to prevent microbial degradation. This ensures the quality and longevity of the leather materials.
Personal care and cosmetic formulators incorporate it at low concentrations as a preservative active against a broad range of bacteria and fungi, ensuring product safety and shelf stability.
THPS is commercially available as an aqueous solution, typically at 75% active content. It is supplied in technical grade for industrial water treatment and textile applications.
Select grades meet specifications for cosmetic preservation use. Packaging options generally include drums and intermediate bulk containers (IBCs) to suit varying procurement volumes and logistics.
Physical Properties
| Melting Point | -35°C |
| Boiling Point | 111°C |
| Density | 1.41 g/cm³ @ Temp: 20 °C |
| Flash Point | 96 °C |
| Color | Colorless to Almost colorless |
| Form | liquid |
| Water Solubility | >=10 g/100 mL at 18 ºC |
| Vapor Pressure | 0Pa at 20℃ |
| Log P | -9.8 |
Safety & Handling (Learn More)
Trade & Regulatory
| HS Code | 29319019 |
| UN Number | 2922 |
| ADR Class | 8 |
| Packing Group | III |
| Storage Class | 6.1C - Combustible acute toxic Cat.3 toxic compounds or compounds which causing chronic effects |
| WGK (Germany) | 1 |
Documentation
Other Names
Retardol S|Pyroset TKO|Octakis(hydroxymethyl)phosphonium sulfate|NCI-C55050|Phosphonium, tetrakis(hydroxymethyl)-, sulfate (2:1) (salt)|Phosphonium, tetrakis(hydroxymethyl)-, sulfate (2:1)|THPS
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