1-Hydroxy Ethylidene-1,1-Diphosphonic Acid (HEDP)
CAS No. 2809-21-4 Molecular Formula: C2H8O7P2
Molecular weight: 206.02
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 additives in 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 (as Cl- ) 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 | |
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.
