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Organic Acids

Etidronic acid

CAS: 2809-21-4

Overview

Etidronic acid (CAS 2809-21-4 ), commonly known as HEDP or Oxyethylidenediphosphonic acid, is a phosphonate chelating agent used across water treatment, industrial cleaning, and personal care manufacturing.

It binds metal ions and inhibits scale formation, preventing corrosion and deposit buildup in process systems and formulated products. In water treatment and oilfield operations, HEDP controls calcium carbonate and calcium sulfate scale.

This chemical is essential for cooling towers, boilers, and injection systems, effectively extending equipment service life. Personal care formulators use it as a stabilizer in oxidative hair color and bleaching products.

It sequesters trace metals that would otherwise degrade peroxide systems, ensuring product stability. Textile and paper processors apply it to prevent metal-catalyzed degradation during bleaching and dyeing processes.

This application protects fiber quality and ensures process consistency across manufacturing lines. In industrial cleaning and detergent formulations, it disperses iron and hardness ions to improve wash performance.

The agent prevents redeposition of minerals on surfaces during the cleaning cycle. Etidronic acid is supplied as an aqueous solution, most commonly at sixty percent active content for industrial use.

While other concentrations are available for specific applications, Technical grade is the standard for water treatment. Higher-purity grades serve personal care and specialty formulation markets globally.

Bulk liquid supply in IBC containers or drums is the typical commercial format for this product. We ensure all shipments meet rigorous industrial specifications for consistency and performance in your applications.

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Physical Properties

Melting Point115-117 °C
Boiling Point578.8±60.0 °C(Predicted)
Density1.45 (60% aq.)
Appearancelight beige powder
Colorwhite
FormPowder
Water SolubilitySoluble in water.
Vapor Pressure0Pa at 25℃
pHpH (1.7→100, 25℃) : 1.3~1.8
Log P-3.5

Safety & Handling

Danger GHS05 GHS07 GHS08 Hazard Statements H290 May be corrosive to metals H302 Harmful if swallowed H314 Causes severe skin burns and eye damage H318 Causes serious eye damage H371 May cause damage to organs H413 May cause long lasting harmful effects to aquatic life Precautionary Statements P234 Keep only in original packaging. P260 Do not breathe dust/fume/gas/mist/vapours/spray. P264 Wash … thoroughly after handling. P270 Do not eat, drink or smoke when using this product. P273 Avoid release to the environment. P280 Wear protective gloves/protective clothing/eye protection/face protection. P316 Get emergency medical help immediately. P317 Get emergency medical help. P321 Specific treatment (see … on this label). P330 Rinse mouth. P363 Wash contaminated clothing before reuse. P390 Absorb spillage to prevent material damage. P405 Store locked up. P406 Store in a corrosion-resistant/… container with a resistant inner liner. P501 Dispose of contents/container in accordance with local regulations. P264+P265 Wash … thoroughly after handling. P301+P317 Get emergency medical help. P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing. P308+P316 Get emergency medical help immediately. P301+P330+P331 Rinse mouth. Do NOT induce vomiting. P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Rinse skin with water/shower. P305+P354+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 Code29319099
UN Number3265
Storage Class8A - Combustible corrosive hazardous materials
WGK (Germany)2

Other Names

Oxyethylidenediphosphonic acid | Hydroxyethanediphosphonic acid | HEDP | Etidronsäure | Ethane-1-hydroxy-11-diphosphonic acid | Ethane-1-hydroxy-11-diphosphonate | Ethane-1-hydroxy-11-bisphosphonic acid | Ethane-1-hydroxy-11-bisphosphonate

Related Products

Chemical Properties

CAS Number
2809-21-4
EC Number
220-552-8
Mol. Weight
206.03
HS Code
29319099

Industries

Documentation