1-Hydroxy Ethylidene-1, 1-Diphosphonic Acid (HEDP)

CAS No.:

2809-21-4

Molecular formula/weight:

C₂H₈O₇P₂=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. HEDP shows excellent scale and corrosion inhibition effects under temperature 250℃. 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, HEDP has good antiscale and visible threshold effects. When built together with other water treatment chemicals, it shows good synergistic effects.

The solid state of HEDP is crystal powder, suitable for usage in winter and freezing districts. Because of its high purity, it can be used as cleaning agent in electronic fields and as additives in daily chemicals.

SPECIFICATION:

Items

Liquid

Solid

Appearance

Colorless or pale yellow solution

White crystalline powder

Active content

60.0% min

90.0 min.

Phosphorous acid (as PO₃^3-)

2.0% max.

0.8 max

Phosphoric acid  (as PO₄^3- )

0.8% max.

0.5 max

Chloride (as Cl^-) ppm

100 max

100 max

PH value of 1% solution

2.0 max. 

2.0 max

Density (20℃)g/cm³

1.44 min

Fe mg/L

10 max. 

5 max

Color(Hazen)

50 max

Ca sequestration (mg CaCO₃/g)

500 min

APPLICATION:

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:

Liquid:250 kg net PE drums or 1250kg net IBC.  

Solid: 25 kg net bags.