HEDP

1-Hydroxy Ethylidene-1, 1-Diphosphonic Acid (HEDP)
CAS No: 2809-21-4
Alias: 1-Hydroxy Ethylidene-1, 1-Diphosphonic Acid, Dequest 2010, HEDPA
Molecular formula: C2H8O7P2 Relative molecular mass: 206.02
Structural formula:

Product Property
HEDP 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 temperature 250oC HEDP has good chemical stability under high pH value, hard to be hydrolyzed, and hard to be decomposed under ordinary light and heat conditions. Its acid/alkali and chlorine oxidation tolerance are better than that of other organic phosphoric acids (salt). HEDP can react with metal ions in water system to form hexa-element chelating complex, with calcium ion in particular. Therefore, HEDP has good antiscale and visible threshold effects. When built together with other water treatment chemicals, it shows good synergistic effects.
Index Name Specifications
Appearance Clear, Colorless to pale yellow aqueous solution White powder
Active Content(as HEDP),% 58.0-62.0 89.0
Phosphorous Acid (as PO33- )% 1.0max. 0.80
Phosphorous Acid (as PO43- )% 0.6max. 0.50
Acetic Acid % 0.5max. ---
Chloride(as Cl-) , ppm 100.0max 0.5
PH (1% solution) 2.0max 2.0
Density(20oC) g/cm3 1.43-1.47 --
Iron (as Fe) , ppm 10.0max 5.0
Ca sequestration, mg CaCO3/g 500.0min ---
Identification: Qualified Active Content: (as HEDP H2O) % 98.0
Specification
Application scope and Usage
HEDP is used as scale and corrosion inhibition in circulating cool water system, oil field and low-pressure boilers in fields such as electric power, chemical industry, metallurgy, fertilizer, etc. In light woven industry, HEDP is used as detergent for metal and nonmetal. In dyeing industry, HEDP is used as peroxide stabilizer and dye-fixing agent; in non-cyanide electroplating, HEDP is used as chelating agent. The dosage of 1-10mg/L is preferred as scale inhibitor, 10-50mg/L as corrosion inhibitor, and 1000-2000mg/L as detergent. Usually, HEDP is used together with polycarboxylic acid.
Package and Storage
It is usually packed in 30kg or 250kg plastic drum, and can be also determined by users. It can be stored for ten months in shady and dry place under room condition.
Safety Protection:
This product is in acidity. Avoid contact with eye and skin. Rinse with plenty of water shortly after being bodily stained.

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