Sodium tripolyphosphate CAS#7758-29-4
Effective builder in detergents – Enhances cleaning power by preventing scale formation through strong metal ion chelation.
Water softening agent – Softens hard water, improving detergent performance and protecting appliances.
Food preservative – Retains moisture in seafood and meat, helping maintain freshness and texture.
Stable crystalline forms – Available in multiple forms, with Phase II offering optimal stability for industrial applications.
Sodium tripolyphosphate (STPP, Na₅P₃O₁₀, CAS 7758-29-4) is a white crystalline phosphate compound widely used as a builder in detergents (making up 50% of global consumption), water softener, and food preservative (E451). Its strong ability to chelate metal ions (such as Ca²⁺/Mg²⁺) improves cleaning efficiency by preventing scale buildup. In food processing, it helps retain moisture in seafood and meats. STPP exists in three crystalline forms (Phase I/II/hexahydrate), with Phase II being the most stable for industrial use.
Parameters
Melting point | 622 °C |
bulk density | 1000kg/m3 |
density | 2.52 g/cm3 (20℃) |
vapor pressure | <0.1 hPa (20 °C) |
refractive index | 1.658 |
storage temp. | Storage temperature: no restrictions. |
solubility | H2O: may be clear to slightly hazy |
form | Powder/Solid |
color | White |
Odor | Odorless |
PH | 9.0-10.0 (25℃, 1% in H2O) |
PH Range | 9.5 - 10.3 at 1 g/l at 20 °C |
Water Solubility | 20 g/100 mL (20 ºC) |
Sensitive | Hygroscopic |
Merck | 14,8697 |
Stability: | Stable. Incompatible with strong oxidizing agents, strong acids. Hygroscopic. |
InChIKey | HWGNBUXHKFFFIH-UHFFFAOYSA-I |
LogP | -4.691 (est) |
CAS DataBase Reference | 7758-29-4(CAS DataBase Reference) |
EPA Substance Registry System | Sodium tripolyphosphate (7758-29-4) |
Safety Information
Hazard Codes | Xi |
Risk Statements | 36/37/38 |
Safety Statements | 26-36-24/25 |
WGK Germany | 1 |
RTECS | YK4570000 |
F | 3 |
TSCA | Yes |
HS Code | 28353110 |
Hazardous Substances Data | 7758-29-4(Hazardous Substances Data) |
Toxicity | LD50 orally in rats: 6.50 g/kg (Smyth) |
Sodium tripolyphosphate is used in various applications such as water softening, heavy-duty fabric washing, automatic dishwashing, drilling fluid cleaning, and as a liquid cattle feed supplement. It also serves as a peptizing, emulsifying, and dispersing agent, as well as a stabilizer for hydrogen peroxide solutions. Additionally, it functions as a preservative for seafood, meats, poultry, and animal feeds. In polysaccharide-based drug delivery, it acts as a polyanion crosslinker. Sodium tripolyphosphate is also utilized as a sealant for leaking farm ponds and as a chelating agent for calcium and magnesium. Other applications include ceramics, leather tanning, flame retardants, paper pulping, paper coatings, textile processing, ore flotation, anticorrosion pigments, and rubber production.
