SoleChem

Sodium tripolyphosphate

Sweeteners & Food Additives Textile, Leather & Paper
CAS
7758-29-4
EC
231-838-7
Mol. Weight
367.86 g/mol

Description

Sodium tripolyphosphate (CAS 7758-29-4), commonly known as STPP or E451i, is a polyphosphate salt used across detergent manufacturing, food processing, and industrial treatment applications.

It functions primarily as a sequestrant, builder, and dispersing agent, binding calcium and magnesium ions to improve process efficiency and product performance across various sectors.

In detergent and cleaning product formulations, STPP acts as a builder that softens water by sequestering hardness ions, boosting surfactant performance in both household and industrial cleaners.

Food manufacturers use it under the E451i designation as a moisture-retention and texture agent in processed meats, seafood, and dairy products to maintain quality and yield.

Water treatment operations rely on STPP to control scale formation and disperse mineral deposits in industrial cooling and boiler systems, ensuring long-term equipment protection and efficiency.

In ceramics and paper production, it functions as a deflocculant, reducing slurry viscosity and improving material processability during the manufacturing and refining stages of production.

Sodium tripolyphosphate is supplied as a white powder or granule, with granulated forms preferred where dust control matters in bulk handling and large-scale industrial operations.

Standard commercial grades include food-grade (FCC, E451i compliant) and technical-grade for industrial applications. Both anhydrous and hydrated forms are available for global trade.

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Physical Properties

Melting Point 622 °C
Density 2.52 g/cm³
Appearance white or colourless crystals, granules or powder
Color White
Odor Odorless
Form Powder/Solid
Water Solubility 20 g/100 mL (20 ºC)
Vapor Pressure <0.1 hPa (20 °C)
Refractive Index 1.658
pH 9.0-10.0 (25℃, 1% in H2O)
Log P -4.691 (est)

Safety & Handling (Learn More)

Warning GHS07
Hazard Statements
H315 Causes skin irritation
H319 Causes serious eye irritation
H335 May cause respiratory irritation
Precautionary Statements
P261 Avoid breathing dust/fume/gas/mist/vapours/spray.
P264 Wash … thoroughly after handling.
P271 Use only outdoors or in a well-ventilated area.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
P319 Get medical advice/attention if you feel unwell.
P321 Specific treatment (see … on this label).
P405 Store locked up.
P501 Dispose of contents/container in accordance with local regulations.
P264+P265 Wash … thoroughly after handling.
P302+P352 IF ON SKIN: Wash with plenty of water.
P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P332+P317 Get emergency medical help.
P337+P317 If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P362+P364 Take off contaminated clothing and wash it before reuse.
P403+P233 Store in a well-ventilated place. Keep container tightly closed.
P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code 28353100
Storage Class 11 - Combustible Solids
WGK (Germany) 1

Documentation

Other Names

E451i|sodium tripolyphosphate anhydrous|Pentasodium triphosphate|STPP|Armofos|Thermphos|Rhodiaphos LV|Thermphos N

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