1-Hydroxy Ethylidene-1,1-Diphosphonic Acid
(HEDP)
CAS No. 2809-21-4
Molecular Formula: C2H8O7P2
Molecular weight: 206.02
Structural Formula
Properties:
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. It 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 organophosphoric acids(salt).
HEDP can react with metal ions in water system to form hexa-element chelating complex, with calcium ion in
particular. Therefore, it has good antiscale and visible threshold effects. When built together with other water
treatment chemicals, it shows good synergistic effects.
Solid HEDP is crystal powder, suitable for usage in winter and freezing districts. Due to its high purity, it can be
used as cleaning agent in electronic fields and as additivesin daily chemicals.
Specification:
Items Index
Appearance Clear, Colorless to pale yellow aqueous solution White crystal powder
Active content(HEDP)% 58.0-62.0 90.0min
Phosphorous acid(as PO33- )% 1.0 max 0.8 max
Phosphoric acid(as PO43-)% 0.6 max 0.5 max
Chloride(asCl- )ppm 100.0 max 100.0max
pH (1%solution) 2.0 max 2.0 max
Density (20℃)g/cm3 1.43-1.47 -
Fe, mg/L 10.0 max 5.0 max
Colour APHA(Hazen) 30.0 max -
Acetic acid% 0.5 max
Ca sequestration(mg CaCO3/g ) 500.0 min
www.watertreatmentchem.com
2Organophosphine antiscale and corrosion inhibitor, Chelants
Usage:
HEDP is used as scale and corrosion inhibition, often build with polycarboxylic acid, 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, it is used as peroxide stabilizer and dye-fixing agent; In non-cyanide
electroplating, it is used as chelating agent.
Package and Storage:
Liquid:200L plastic drum, IBC(1000L), customers' requirement.
Solid: 25kg/bag, customers' requirement.
Storage for ten months in room shady and dry place.
Safety Protection:
Acidity, Avoid contact with eye and skin, once contacted, flush with water.
