Disodium hydrogen phosphate, also known as sodium phosphate dibasic, is a sodium salt of phosphoric acid. It is a white powder that is highly hygroscopic and water soluble. Therefore, it is commercially employed as an anti-caking additive in powdered products, available in both the hydrated and anhydrous forms.
Disodium phosphate is produced by reacting phosphoric acid with sodium carbonate which also serves as intermediates for other sodium phosphates.
Disodium phosphate can also be produced by reacting phosphoric acid with two equivalent of sodium hydroxide. This reaction is a neutralization reaction producing the aqueous salt of disodium phosphate and water. By changing the amount of sodium hydroxide added, monosodium phosphate and trisodium phosphate can be obtained. Finally, water is removed to obtain the white solid of disodium phosphate.
Disodium phosphate is used as an antioxidant, stabilizer, emulsifier and anti-caking in food industry. In food, it is used to adjust pH, prevent coagulation in the preparation of condensed milk and as an anti-caking additive in powdered products. It prevents or slows down the growth of bacteria and other microorganisms on food. It also helps to form puddings by acting as a protein coagulate, it even decreases the cooking time of various products such as pasta, hot cereals, etc.
Disodium Phosphate is used in industrial water boilers to soften the hard water and reduce the formation of scales. Disodium Phosphate is used as a disinfectant, fungicide and sanitizer. Disodium Phosphate is used as a water-proofing and fire retardant agent in textiles, paper, and wood processing industries.