Phosphoric Acid CAS 7664-38-2
Food Additives 2025-03-20
Basic Information
| Parameter | Details |
|---|---|
| CAS Number | 7664-38-2 |
| Synonyms | Orthophosphoric acid, phosphoric(V) acid |
| Chemical Formula | H₃PO₄ |
| Molecular Weight | 98.00 g/mol |
| Physical State | Colorless, odorless, viscous liquid or crystalline solid |
| Density | 1.685–1.87 g/cm³ (25°C) |
| Melting Point | 42–42.4°C |
| Boiling Point | 158–261°C |
| Solubility | Miscible with water; soluble in ethanol |
Key Applications
| Industry | Uses |
|---|---|
| Industrial | Metal surface treatment (phosphating, polishing), phosphate fertilizers |
| Food | Acidulant, yeast nutrient (e.g., cola drinks) |
| Pharmaceuticals | Drug intermediate (e.g., sodium glycerophosphate) |
| Materials | Flame retardants, catalysts, corrosion inhibitors |
| Others | Sugar refining, plastics, dyes, printing inks |
Safety Overview
| Aspect | Details |
|---|---|
| Hazard Classification | Corrosive; irritates eyes, skin, and respiratory tract |
| PPE | Chemical-resistant gloves, goggles, apron; ventilation |
| First Aid | Rinse skin/eyes with water; seek fresh air for inhalation; ingest milk/egg white |
| Storage Conditions | Cool, dry place (<30°C, <80% humidity); separate from combustibles/alkalis |
Technical Notes
Acidity: Triprotic acid (pKa₁=2.1. pKa₂=7.2. pKa₃=12.3 at 25°C).
Stability: Stable at room temperature; decomposes at >200°C to form pyrophosphoric acid.
Handling: Avoid contact with metals, strong bases, and heat. Seal containers tightly to prevent moisture absorption.
