DESCRIPTION

Trisodium pyrophosphate occurs as a white powder or grains. It is anhydrous or contains one molecule of water of hydration. This ingredient occurs as a 1:1 mixture of dihydrogen disodium diphosphate and tetrasodium diphosphate that upon dissolution in water becomes equivalent to trisodium pyrophosphate. It is manufactured by continuously calcinating a solution of caustic soda and phosphoric acid in a drum dryer with subsequent milling and sieving steps. It is stable in air, and soluble in water. The pH of a 1% (w/v) aqueous solution is 6.7–7.5.