• CAS Number: 2809-21-4

• Molecular Formula: C₂H₈O₇P₂

• Molecular Weight: 206.02

• Structural Formula: 

   

Properties:

1-Hydroxy Ethylidene-1,1-Diphosphonic Acid  is an organophosphoric acid corrosion inhibitor. It can chelate with Fe, Cu, and Zn ions to form stable chelating compounds. It can dissolve the oxidized materials on these metals' surfaces. HEDP shows excellent scale and corrosion inhibition effects under temperatures of 250°C. HEDP has good chemical stability under high pH values, is difficult to hydrolyze, and is resistant to decomposition under normal light and heat conditions. Its acid/alkali and chlorine oxidation tolerance are better than those of other organophosphoric acids (salts). HEDP can react with metal ions in water systems to form hexa-element chelating complexes, particularly with calcium ions. Therefore, HEDP has good anti-scaling and visible threshold effects. When combined with other water treatment chemicals, it shows good synergistic effects.

The solid form of HEDP is a crystal powder, suitable for use in winter and freezing regions. Due to its high purity, it can be used as a cleaning agent in the electronics field and as an additive in daily chemicals.

Specification:

• Appearance: Clear, colorless to pale yellow aqueous solution / White crystal powder

• Active Content (HEDP), %: 58-62 (liquid) / 90.0 min (solid)

• Active Content (HEDP·H2O), %: - / 98.0 min (solid)

• Phosphorous Acid (as PO33-), %: 2.0 max (liquid) / 0.8 max (solid)

• Phosphoric Acid (as PO43-), %: 0.8 max (liquid) / 0.5 max (solid)

• Chloride (as Cl-), ppm: 100.0 max (liquid) / 100.0 max (solid)

• pH (1% water solution): 2.0 max (liquid) / 2.0 max (solid)

• Density (20°C), g/cm³: 1.43-1.47 (liquid)

• Iron, mg/L: 20.0 max (liquid) / 10.0 max (solid)

• Color APHA (Hazen): 40.0 max (liquid)

• Calcium Sequestration (mg CaCO3/g): 500.0 min

Usage:

HEDP is used as a scale and corrosion inhibitor in circulating cooling water systems, oil fields, and low-pressure boilers in fields such as electric power, chemical industry, metallurgy, fertilizers, etc. In the light textile industry, HEDP is used as a detergent for metals and nonmetals. 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. The dosage of 1-10mg/L is preferred as a scale inhibitor, 10-50mg/L as a corrosion inhibitor, and 1000-2000mg/L as a detergent. Usually, HEDP is used together with polycarboxylic acid.

Package and Storage:

• Liquid HEDP: 200L plastic drum, IBC (1000L), customer's requirement.

• Solid HEDP: 25kg/bag, customer's requirement.

• Storage for ten months in a cool, dry place.

Safety Protection:

Acidic, avoid contact with eyes and skin, flush with water if contacted.