Reaction #543552

Reaction equation

pentasodium triphosphate

Na5P3O10

→

orthophosphate

Yield 8.0%

diphosphate

Yield 15.0%

Solvents

water

Conditions

Workup

1. 1
   Othercrystallizes with 6 H2O
2. 2
   workup.DISSOLUTIONAbout 17 g of the anhydrous salt dissolve in 100 g of water at room temperature
3. 3
   workup.DISSOLUTIONabout 20 g dissolve at 60°
4. 4
   workup.DISSOLUTIONabout 32 g dissolve at 100°
5. 5
   Temperatureafter heating the solution for two hours at 100°

Procedure

The industrially important pentasodium triphosphate, Na5P3O10 (sodium tripolyphosphate) is a nonhygroscopic, white, water-soluble salt which is anhydrous or crystallizes with 6 H2O and has the general formula NaO—[P(O)(ONa)—On]—Na where n=3. About 17 g of the anhydrous salt dissolve in 100 g of water at room temperature, about 20 g dissolve at 60°, and about 32 g dissolve at 100°; after heating the solution for two hours at 100°, about 8% orthophosphate and 15% diphosphate are produced by hydrolysis. In the case of the preparation of pentasodium triphosphate, phosphoric acid is reacted with soda solution or sodium hydroxide solution in the stoichiometric ratio and the solution is dewatered by spraying. Similarly to Graham's salt and sodium diphosphate, pentasodium triphosphate dissolves many insoluble metal compounds (including lime soaps, etc.). Pentapotassium triphosphate, K5P3O10 (potassium tripolyphosphate), is commercially available, for example, in the form of a 50% strength by weight solution (>23% P2O5, 25% K2O). The potassium polyphosphates are widely used in the detergents and cleaners industry.

Source