Shandong Huashang Chemical Co., Ltd. is a high-tech enterprise focused on industry of fine chemicals research and develop, produce and sale. Shandong Huashang Chemical Co., Ltd. is located in Shan Dong Ji Nan China. we have the ability to provide you high quality products. More than 90 % of our products are exported to developed countries and regions such as north America, Europe, Japan, South Korea and the Middle East.
1. Basic Product Profile
- Full IUPAC Name: 1-hydroxyethane-1,1-diylbis(phosphonic acid)
- Aliases: HEDP, Etidronic Acid
- CAS Number: 2809-21-4
- EINECS: 220-466-6
- Molecular Formula: C2H8O7P2
- Molecular Weight: 206.03
- Chemical Classification: Organic phosphonic acid scale inhibitor, metal chelating agent, water treatment chemical
- Core Advantages
Organic diphosphonic acid with strong chelation, scale inhibition and metal corrosion inhibition performance. Excellent stability under high temperature and high alkali conditions, not easy to hydrolyze. Forms stable soluble complexes with Ca, Mg, Fe, Zn metal ions. Widely used in circulating cooling water treatment, boiler descaling, metal surface cleaning, daily chemical additives and electroplating industry.
2. Physical & Chemical Properties
2.1 Physical Index
- Appearance: Colorless to pale yellow transparent viscous liquid
- Odor: Slight acidic odor
- Solubility: Fully miscible with water, ethanol; insoluble in aliphatic hydrocarbon solvents
- Density (20℃): 1.43–1.48 g/cm3
- pH (1% aqueous solution): <2.0
- Hygroscopy: Highly hygroscopic liquid
- Thermal Performance: Stable below 100℃, no decomposition under normal heating
2.2 Chemical Properties
- Dual phosphonic acid groups + hydroxyl group: Multi-site chelation structure, powerful capture of hard metal ions
- Acid-base characteristic: Tetraprotic weak organic acid, can react with alkali to generate HEDP salts (sodium salt, potassium salt)
- Scale inhibition mechanism: Adsorbs on crystal surface to distort calcium carbonate/calcium sulfate crystal growth, prevent scale deposition
- Corrosion inhibition: Forms protective passivation film on carbon steel, copper surface
- Thermal & hydrolysis stability: Resistant to hydrolysis under high temperature, better than polyphosphate inorganic scale inhibitors
- Compatibility: Compatible with polyacrylic acid, quaternary ammonium bactericides; incompatible with strong oxidants, high concentration heavy metal salts
3. Main Application Fields
3.1 Industrial Circulating Water Treatment (Core Usage)
Scale and corrosion inhibitor for cooling tower, central air conditioning circulating water, industrial boiler water system; inhibits calcium, magnesium salt scaling and pipeline metal rusting.
3.2 Metal Surface Treatment
Cleaning agent for iron, steel, copper, aluminum alloy surface descaling and rust removal auxiliary; chelating stabilizer for electroplating bath.
3.3 Daily Chemical & Cosmetic Raw Material
Stabilizer and chelator in shampoo, body wash, skin care products to shield metal ions and avoid formula discoloration.
3.4 Textile & Dyeing Auxiliary
Water softener in printing and dyeing process, prevents fabric hardening and color unevenness caused by hard water metal ions.
4. Quality Specification Table
| Test Item | Standard Index |
| CAS No. | 2809-21-4 |
| Molecular Formula | C2H8O7P2 |
| Molecular Weight | 206.03 |
| Appearance | Colorless to pale yellow viscous liquid |
| Active HEDP Content | 50% min Industrial Grade; 60% High Concentration Grade |
| Phosphorous Acid (as H3PO3) | ≤1.0% |
| Chloride (Cl) | ≤0.10% |
| Density (20℃) | 1.43–1.48 g/cm3 |
| pH (1% Solution) | ≤2.0 |
| Bulk Package | 250L plastic drum, 1000L IBC tote tank |
| Sample Package | 1L / 5L sealed plastic bottle |
| Storage Requirements | Hermetic cool dry warehouse ≤25℃; isolate alkaline substances, avoid direct contact with metal containers for long-term storage |
| Transportation Rule | Weak acidic organic phosphonic liquid; acid-resistant sealed packaging required during transit |
| Shelf Life | 24 months under intact sealed packaging |
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