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

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 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