Sodium Tripolyphosphate → Pyrophosphate

HRID 2223012Notes

Reaction equation

HRID 2223012 reaction equation
[O-:1][P:2]([O:5][P:6]([O:9]P([O-])([O-])=O)([O-:8])=[O:7])(=[O:4])[O-:3].[Na+].[Na+].[Na+].[Na+].[Na+]>O>[P:2]([O-:5])([O-:4])([O-:3])=[O:1].[O-:3][P:2]([O:5][P:6]([O-:9])([O-:8])=[O:7])(=[O:1])[O-:4]

Participants

4

Reactant 1

HCID 24455Sodium Tripolyphosphate2×

Product 2

HCID 1061PhosphateYield 8%HCID 644102PyrophosphateYield 15%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

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)—O]n—Na where n=3. About 17 g of the crystalline anhydrous salt dissolve at room temperature in 100 g of water, approx. 20 g at 60°, and about 32 g at 100°; after heating the solution to 100° for two hours, about 8% orthophosphate and 15% diphosphate are formed by hydrolysis. In the case of the preparation of pentasodium triphosphate, phosphoric acid is reacted with sodium carbonate 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% by weight solution (>23% P2O5, 25% K2O). The potassium polyphosphates are widely used in the detergent industry.

Workup

  1. customcrystallizes with 6 H2O
  2. dissolutionAbout 17 g of the crystalline anhydrous salt dissolve at room temperature in 100 g of water
  3. customat 60°
  4. customat 100°
  5. temperatureafter heating the solution to 100° for two hours

Sources & evidence

ORD record
ord-bd8bcc2d13b2402098022fba7e1d43b9
Source dataset
uspto-grants-2008_05
Patent number
US07375070B2

Reaction notes

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