Hydroxy Phosphono Acetic Acid, 2-Hydroxy Phosphono Carboxylic Acid, HPAA, 23783-26-8

2-HYDROXY PHOSPHONOACETIC ACID (HPAA)

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

Short Identity Section

Detailed Identification

Description:
HPAA is an organophosphorus corrosion inhibitor with excellent chemical stability. It is resistant to hydrolysis and exhibits strong resistance to both acidic and alkaline environments. HPAA is characterized by low toxicity and environmental compatibility. The product significantly improves zinc solubility and provides corrosion inhibition performance reported to be substantially higher than traditional phosphonates such as HEDP and EDTMP. When formulated with low molecular weight polymers, HPAA demonstrates enhanced corrosion protection efficiency. HPAA provides higher biodegradability (93%) and a much better environmental profile versus other available programs.

2. PHYSICAL AND CHEMICAL PROPERTIES

Note: Values are typical and may vary by source. The density of the 50% aqueous solution is typically 1.37 g/cm³. The pH of a 1% solution is strongly acidic (< 2.0).

3. SOLUBILITY PROFILE

Note: HPAA is miscible in water, methanol, and ethylene glycol.

4. CHEMICAL PROPERTIES AND REACTIONS

Incompatibilities

• Strong oxidizing agents

• Strong bases (risk of exothermic reaction)

• Active metals (hydrogen gas may be released)

Chemical Reactions

• Protonation: Three ionizable protons create a pH-dependent speciation profile critical for chelating activity.

• Chelation: Forms complexes with metal ions (Ca²⁺, Mg²⁺, Fe²⁺, Zn²⁺).

• Hydrolysis: The C-P bond resists hydrolysis even under aggressive acidic or basic conditions.

5. SPECIFICATIONS

Packaging Options

6. APPLICATIONS AND INDUSTRIAL USES

6.1 Primary Application: Cathodic Corrosion Inhibitor

6.2 Performance and Benefits

• Excellent cathodic corrosion inhibition performance

• High chemical and thermal stability

• Resistant to hydrolysis

• Effective in acidic and alkaline conditions

• Enhances zinc salt solubility

• Low toxicity and environmentally acceptable

• Compatible with low molecular weight polymer formulations

• Suitable for various industrial water treatment applications

• Corrosion inhibition ability 5–8 times better than HEDP and EDTMP

• Cost-effective alternative to sodium molybdate

• Higher biodegradability (93%) and better environmental profile

6.3 Usage Recommendations

HPAA is commonly used in combination with zinc salts for enhanced corrosion protection. When formulated with low molecular weight polymers, corrosion protection efficiency is further enhanced. It is also suitable for applications where molybdate discharge is regulated or all-organic cooling water treatment is desired.

7. BIOLOGICAL AND STRUCTURAL PROPERTIES

Note: This product is an industrial corrosion inhibitor. It is not intended for biological, pharmaceutical (except pharmaceutical water systems), or food applications.

8. BIOCHEMICAL APPLICATIONS

Note: Not applicable for this industrial corrosion inhibitor.

9. SAFETY AND TOXICOLOGY

9.1 Acute Toxicity

Note: The ECHA harmonized classification lists Skin Corr. 1B and Eye Dam. 1. Some SDSs report an oral ATE of 1,260 mg/kg, while other sources cite an LD₅₀ of 2,700 mg/kg.

9.2 Chronic Toxicity

9.3 GHS Classification (Harmonized)

Note: The harmonized classification from ECHA (Annex VI, CLP Regulation) is provided above. Some notifiers also include Eye Dam. 1 (H318) and STOT SE 2 (H371).

9.4 Precautionary Statements

9.5 Safety Precautions and PPE

Hazards:

• Harmful if swallowed

• Causes severe skin burns and eye damage

• May cause an allergic skin reaction

• May cause damage to organs through prolonged or repeated exposure

PPE (recommended):

• Chemical-resistant gloves (nitrile, neoprene, PVC)

• Safety goggles (EN 166) or face shield

• Protective clothing (acid-resistant)

• Respiratory protection (if dust/aerosol is generated)

9.6 Environmental Fate

Note: HPAA is readily biodegradable (93%) and has a lower environmental impact compared to some traditional chelating agents.

10. TRANSPORT INFORMATION

Note: Transport classification is UN 3265, Class 8, Packing Group II due to the corrosive nature of the product.

11. REGULATORY INFORMATION

Note: HPAA is subject to TSCA Inventory requirements in the USA and requires valid REACH registration for supply in the EU. It is listed as active in the TSCA Inventory.

12. STORAGE AND HANDLING

Note: Storage at -20°C is recommended by some sources. The recommended storage period is 12 months under proper conditions.

13. FIREFIGHTING MEASURES

Note: HPAA is non-flammable. Firefighters should use appropriate respiratory protection.

14. ACCIDENTAL RELEASE MEASURES

Note: Spills can be neutralized with sodium bicarbonate or lime.

15. FIRST AID MEASURES

Note: HPAA is corrosive. Immediate flushing with water is essential for skin and eye contact.

16. RAW MATERIALS AND DOWNSTREAM PRODUCTS

16.1 Raw Materials (Upstream)

16.2 Downstream Products

17. SECTORAL SUITABILITY AND USAGE LEVELS

18. CARBON DIOXIDE ABSORPTION AND REAGENTS

Not applicable. HPAA is an industrial corrosion inhibitor and is not used for CO₂ absorption or as a chemical reagent.

19. DERIVATIVES AND RELATED COMPOUNDS

Note: HPAA demonstrates 5–8 times better corrosion inhibition than HEDP and EDTMP.

20. SUMMARY AND CRITICAL WARNINGS

SUMMARY

HPAA (2-Hydroxy Phosphonoacetic Acid) is an organophosphorus corrosion inhibitor with excellent chemical stability. It is resistant to hydrolysis and exhibits strong resistance to both acidic and alkaline environments. HPAA is characterized by low toxicity and environmental compatibility. The product significantly improves zinc solubility and provides corrosion inhibition performance reported to be substantially higher than traditional phosphonates such as HEDP and EDTMP. When formulated with low molecular weight polymers, HPAA demonstrates enhanced corrosion protection efficiency. HPAA provides higher biodegradability (93%) and a much better environmental profile versus other available programs.

It appears as a dark brown to amber viscous liquid. Its density is 1.30–1.42 g/cm³ (50% solution), pH is ≤2.0 (1% solution), and solid content is ≥50.0%. It is miscible in water.

It is primarily used as a cathodic corrosion inhibitor in oilfield reinjection water systems, cooling water treatment systems, steel and iron industries, petrochemical plants, power generation facilities, and medical/pharmaceutical water systems.

Key Properties

Main Application Areas

Key Safety Points

• CORROSIVE: Causes severe skin burns and eye damage (H314).

• HARMFUL: Harmful if swallowed (H302).

• SENSITIZING: May cause an allergic skin reaction (H317).

• ORGAN DAMAGE: May cause damage to organs through prolonged or repeated exposure (H373).

• PPE REQUIRED: Use acid-resistant gloves, safety goggles/face shield, and protective clothing.

• STORAGE: Store in a cool, dry, well-ventilated area away from direct sunlight. Keep tightly closed in original container.

• DISPOSAL: Dispose of according to local regulations.

Critical Warnings

• HPAA is corrosive; avoid contact with skin and eyes.

• Harmful if swallowed.

• May cause an allergic skin reaction.

• May cause damage to organs through prolonged or repeated exposure.

• This TDS contains complete toxicological, transport, firefighting, and first aid data, but always refer to the supplier’s official SDS/MSDS.

• Do not use this TDS as a substitute for the official SDS/MSDS.

• Users are responsible for determining the suitability of the product for their specific applications and for complying with all applicable regulations and safety requirements.

Disclaimer:
This Technical Data Sheet (TDS) is for informational purposes only. The information provided is based on the original source document, verified CAS/EC numbers, and data completed from reliable sources (ECHA, EPA, manufacturer SDSs). However, the user is solely responsible for determining the suitability of the product for their specific applications and for complying with all applicable regulations and safety requirements. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Users are responsible for testing the product in their own processes and applications. All local, national, and international regulations must be followed when working with HPAA.