Disodium Dihydrogen Pyrophosphate

Disodium dihydrogen pyrophosphate, also known as acidic sodium pyrophosphate, is an inorganic sodium compound with the chemical formula Na₂H₂P₂O₇ and a molar mass of 221.94 g/mol. It appears as a white crystalline powder or melt, readily soluble in water but insoluble in ethanol, with a melting point of 250℃. A 1% aqueous solution has a pH of 4-4.5 and is hygroscopic. Disodium dihydrogen pyrophosphate decomposes into sodium metaphosphate above 220℃ and can form chelates with Mg²⁺ and Fe²⁺.

Products Description

Sodium dihydrogen pyrophosphate, with the chemical formula Na₂H₂P₂O₇, has a relative molecular mass of 221.94. It appears as a white crystalline powder or molten solid, odorless, with a slightly salty taste. Its relative density is 1.86 g/cm³ (25°C), and its refractive index is 1.510 (n₂₀D). It is readily soluble in water, with a solubility of approximately 0.1 g/mL (20°C), and its aqueous solution is acidic, with a pH of approximately 4.0–4.5 (1% solution). It is insoluble in ethanol. This substance is hygroscopic and forms a hexahydrate upon absorbing water. Heating sodium dihydrogen pyrophosphate to above 220°C decomposes it to produce sodium metaphosphate.

Other Names:	Acidic sodium pyrophosphate
Chemical Formula:	Na₂H₂P₂O₇
Molecular Weight:	221.939
CAS	7758-16-9
EINECS	231-835-0

Products Application

In the food industry, it is mainly used as a leavening agent, moisture retainer, and quality improver, commonly found in the processing of bread, biscuits, meat products, and seafood to improve texture and extend shelf life.

In the chemical industry, it is used as a detergent component, electroplating stabilizer, and water treatment agent to chelate metal ions and soften water.

Furthermore, in the feed industry, it is used as a nutrient fortifier, enhancing feed bioavailability by chelating with metal ions.