HEDP
Appearance: Clear, Colorless to pale yellow aqueous solution; White crystal powder
Grade: industrial grade
CAS Number: 2809-21-4
EINECS Number: 220-552-8
Chemical Formula: C2H8O7P2
HS Code:2931900090
Package: 200 kg drum, 1000kg IBC drum, 25kg bag
Product Features
HEDP is an organophosphonate corrosion inhibitor. HEDP shows multifunctional properties that include scale inhibition and corrosion inhibition. HEDP is noted for excellent CaCO3 inhibitor and water hardness stabilizer. HEDP is a very good complexing agent for metal ions like Fe, Cu, and Zn.
HEDP can react with metal ions in a water system to form a hexa-element chelating complex, with calcium ions in particular. When built together with other water treatment chemicals, HEDP shows good synergistic effects. HEDP shows excellent stability under high pH values, is hard to hydrolyze, and is hard to decompose under ordinary light and heat conditions. HEDP shows excellent scale and corrosion inhibition effects at a temperature of 250℃. HEDP acid/alkali and chlorine oxidation tolerance are better than those of other organophosphonate (salts).
HEDP can dissolve the oxidized materials on these metals' surfaces.
HEDP solid form is a white crystalline powder with a melting point of 198-200°C, suitable for use in winter and freezing districts. Highly soluble in water, acids, alkalis, methanol, and ethanol. Because of its high purity, it can be used as a cleaning agent in electronic fields and as an additive in daily chemicals.

Technical Specification
Parameter | Standard | |
Liquid | Solid | |
Appearance | Clear, colorless to pale yellow aqueous solution | White crystal powder |
Active content(HEDP), % | 58-62 | 90.0 min |
Active content (HEDP·H2O), % | - | 98.0 min |
Phosphorous acid (as PO33-), % | 2.0 max | 0.8 max |
Phosphoric acid (as PO43-), % | 0.8 max | 0.5 max |
Chloride (as Cl-), ppm | 100.0 max | 100.0 max |
pH (1% water solution) | 2.0 max | 2.0 max |
Density (20℃), g/cm3 | 1.43-1.47 | - |
Fe, mg/L | 20.0 max | 10.0 max |
Color APHA (Hazen) | 40.0 max | - |
Ca Sequestration (mg CaCO3/g) | 500.0 min | - |
Applications & Usage
HEDP is widely used in several end use applications such as detergents (as chelant), industrial and institutional cleaners, personal care products, water treatment circulating cooling water systems, low-pressure boilers, swimming pool stain prevention, metal ion control, oilfield, textile, paper, peroxide stabilizer, electroplating, HEDP also can be used for formulating RO membrane antiscalants, thermal desalination antiscalants, formulation for treating sterilizers etc.
In the light woven industry, HEDP is used as a detergent for metal and non-metal. In the dyeing industry, HEDP is used as a peroxide stabilizer and dye-fixing agent. In non-cyanide electroplating, HEDP is used as a chelating agent.

