Sodium acid pyrophosphate
General Product Information
| Article | Sodium acid pyrophosphate |
| Synonyms | E450(i), Disodium pyrophosphate, Disodium dihydrogen diphosphate, Diphosphoric acid, Disodium salt, Disodium dihydrogen pyrophosphate, Disodium diphosphate, Sodium acid pyrophosphate, SAPP |
| CAS No. | 7758-16-9 |
| EEG No. | – |
| EINECS No. | 231-835-0 |
| IMO | – |
| Tariff Code | 28353900 |
| UN No. | – |
| VLG/ADR | – |
Description
Sodium acid pyrophosphate is an inorganic phosphate salt widely used in the Food Industry and Technical sectors. It comes as a white, crystalline powder and is known for its good solubility in water and its acid-acting properties. The product functions as a raising agent, stabilizer, pH regulator and metal binder, among others.
Characteristics
- Odor: Odorless.
- Hygroscopic: Yes.
- Color: White.
- Grade: Food.
- Solubility: Highly soluble in water.
- Taste: Neutral to slightly acidic.
- Shape: Crystalline powder.
Physical & Chemical Properties
| Chemical Structure | Na2H2P2O7 |
| Molar Weight | 221.94 g/mol |
| Melting Point | Approx. 220 °C (decomposes). |
| Boiling Point | – |
| Density | Approx. 2.5 g/cm³. |
| Refractive Index | – |
| pH | Approx. 4.0-5.0 (on 1% solution). |
Applications
Sodium acid pyrophosphate is applied in various ways, for instance:
1. Food Industry
Sodium acid pyrophosphate is widely used (including under food additive E450(i)) as a raising agent in baking powders and as a texture improver in meat and potato products. It prevents the formation of unwanted crystals and improves the color and moisture retention of foods. In addition, it acts as a pH regulator and stabilizer.
2. Industrial Applications
At Water Treatment, it prevents scale formation and corrosion by binding calcium ions. It improves washing performance by reducing water hardness from detergents. In metalworking, it is used as a degreasing agent and as a means of preventing corrosion. Finally, sodium pyrophosphate is used in the ceramic and textile industries as a dispersant and stabilizer.
Interessing Links
- Codex Alimentarius (FAO/WHO) – Guidelines and standards for food additives and ingredients.
- European Chemicals Agency (ECHA) – For chemical information and regulations.
- European Food Information Council (EFIC)
- European Food Safety Authority (EFSA) – Information on the safety and uses of food additives and ingredients.
- PubChem – Disodium pyrophosphate – Chemical information by the National Library of Medicine of the National Center for Biotechnology Information (NIH-NCBI).
- Wikipedia – Disodium pyrophosphate