Etidronic Acid CAS# 2809-21-4
Chlorine-Free Eco-Friendly Formula – HEDP is a new-generation chlorine-free complexing agent, making it a safer and more environmentally friendly choice for electroplating and water treatment systems.
Excellent Corrosion and Scale Inhibition – It serves as an effective corrosion inhibitor and scale control agent, helping maintain stable water quality in circulating cooling water systems.
Efficient Water Treatment Performance – As a key organic phosphonic acid water treatment chemical, it provides long-lasting conditioning performance for industrial water systems.
Wide Industrial Applicability – Suitable for electroplating, cooling water circulation, and other industrial water treatment processes requiring reliable scale and corrosion control.
Products Description of Etidronic Acid CAS#2809-21-4
Hydroxyethylidene diphosphonic acid (HEDP) is a new type of chlorine-free electroplating complexing agent. It is mainly used as a key water stabilizer in circulating cooling water systems, where it provides effective corrosion inhibition and scale prevention.
This product is one of the important organic polyphosphonic acid-based water treatment agents. Other related products in this category include aminotrimethylene phosphonic acid (ATMP), [CH₂PO(OH)₂]₃N, and ethylenediaminetetramethylene phosphonic acid (EDTMP). Organic polyphosphonic acids are a class of water treatment chemicals that were developed in the late 1960s and became well established around the 1970s.
Etidronic Acid Chemical Properties
| Melting point | 198~199℃ |
| Boiling point | 578.8±60.0 °C(Predicted) |
| density | 1.45 (60% aq.) |
| vapor pressure | 0Pa at 25℃ |
| storage temp. | Sealed in dry,Room Temperature |
| solubility | Methanol (Slightly), Water (Slightly) |
| pka | 1.35, 2.87, 7.03, 11.3(at 25℃) |
| form | Powder |
| color | white |
| PH | pH (1.7→100, 25℃) : 1.3～1.8 |
| Water Solubility | Soluble in water. |
| Merck | 143863 |
| BRN | 1789291 |
| Stability: | Stable. Incompatible with strong oxidizing agents. |
| InChIKey | DBVJJBKOTRCVKF-UHFFFAOYSA-N |
| LogP | -3.5 |
| CAS DataBase Reference | 2809-21-4(CAS DataBase Reference) |
| EPA Substance Registry System | Etidronic acid (2809-21-4) |
Safety Information
| Hazard Codes | Xi,Xn |
| Risk Statements | 37/38-41-22 |
| Safety Statements | 26-39 |
| RIDADR | UN 3265 |
| WGK Germany | 2 |
| RTECS | SZ8562100 |
| F | 10 |
| TSCA | Yes |
| HazardClass | 8 |
| PackingGroup | II |
| HS Code | 29319090 |
| Hazardous Substances Data | 2809-21-4(Hazardous Substances Data) |
| Toxicity | LD50 oral in mouse: 1800mg/kg |
Product Application of Etidronic Acid CAS#2809-21-4
1-Hydroxyethylidenebis(phosphonic acid) is used as an inhibitor of human protein tyrosine phosphatase and is also suitable for photographic applications. It is applied in bone strengthening, osteoporosis treatment, and the treatment of Paget’s disease of bone.
In industrial applications, it is widely used for corrosion inhibition in circulating cooling water systems, oil fields, low-pressure boilers in electric power, as well as in the chemical, metallurgy, and fertilizer industries. It is also utilized in the formulation of reverse osmosis and thermal desalination anti-scaling agents. In addition, this product is used in detergents, water treatment, cosmetics, and pharmaceutical formulations.
