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.