Tetrasodium pyrophosphate (TSPP) is an inorganic compound with the formula Na4P2O7. It is also known as sodium pyrophosphate, tetrasodium phosphate, or TSPP. It is a white, water-soluble solid when used as a salt. It is made up of sodium ions and pyrophosphate anion. When ingested orally, the toxicity is approximately twice that of table salt. The decahydrate Na4P2O7 • 10(H2O) is also known.
The chemical compound tetrasodium pyrophosphate (TSPP) has the formula Na4P2O7. It is a white, crystalline powder that is extremely water soluble. TSPP is an inorganic compound that belongs to the pyrophosphate salts class.
- Solubility: It is highly soluble in water. It forms an alkaline solution when dissolved in water due to the hydrolysis of the pyrophosphate ion.
- pH: When dissolved in water, it increases the pH of the solution, making it alkaline. The exact pH depends on the concentration of the compound.
- Chelating Agent: It has chelating properties, meaning it can bind with metal ions, particularly calcium and magnesium. This property is often utilized in various industrial and cleaning applications.
- Emulsifying Agent: It can act as an emulsifying agent, helping to disperse and stabilize oil and water mixtures. This property makes it useful in food processing, particularly in meat and dairy products.
- Sequestrant: It is a sequestrant, which means it can bind with metal ions and prevent them from reacting with other components in a formulation. It is commonly used in detergents, cleaning agents, and water treatment applications to prevent the negative effects of metal ions.
Tetrasodium pyrophosphate is produced by the reaction of furnace-grade phosphoric acid with sodium carbonate to form disodium phosphate, which is then heated to 450 °C to form tetrasodium pyrophosphate:
2 Na2HPO4 → Na4P2O7 + H2O
- Food Industry: The Food and Drug Administration (FDA) has approved TSPP as a food additive, and it is used as an emulsifier, sequestrant, and buffering agent. It enhances the texture and moisture retention of processed meats like sausages and hams.
- Water Treatment: As a sequestering agent, TSPP is used in water treatment processes. It aids in the binding and removal of metal ions such as calcium and magnesium, which can cause scaling and impair the efficacy of soaps and detergents.
- Industrial Applications: TSPP is used in a variety of industrial processes such as metal cleaning, oil drilling, textile processing, and ceramics manufacturing. It is used in these applications as a dispersant, buffering agent, and emulsifier.