Disodium pyrophosphate

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Disodium pyrophosphate
Disodium pyrophosphate
Names
IUPAC name
Disodium dihydrogen diphosphate
Other names
Diphosphoric acid, disodium salt
Disodium dihydrogen pyrophosphate
Disodium diphosphate
Sodium acid pyrophosphate, SAPP
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.028.941 Edit this at Wikidata
EC Number
  • 231-835-0
E number E450(i) (thickeners, ...)
UNII
  • InChI=1S/2Na.H4O7P2/c;;1-8(2,3)7-9(4,5)6/h;;(H2,1,2,3)(H2,4,5,6)/q2*+1;/p-2 ☒N
    Key: GYQBBRRVRKFJRG-UHFFFAOYSA-L ☒N
  • InChI=1/2Na.H4O7P2/c;;1-8(2,3)7-9(4,5)6/h;;(H2,1,2,3)(H2,4,5,6)/q2*+1;/p-2
    Key: GYQBBRRVRKFJRG-NUQVWONBAI
  • [Na+].[Na+].[O-]P(=O)(O)OP([O-])(=O)O
Properties
Na2H2P2O7
Molar mass 221.936 g·mol−1
Appearance White odorless powder
Density 2.31 g/cm3
Melting point > 600 °C
11.9 g/(100 mL) (20 °C)
1.4645 (hexahydrate)
Hazards
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
2650 mg/kg (mouse, oral)
Related compounds
Other anions
Other cations
Related compounds
 Tetrasodium pyrophosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Disodium pyrophosphate or sodium acid pyrophosphate (SAPP)

buffering and chelating agent, with many applications in the food industry. When crystallized from water, it forms a hexahydrate, but it dehydrates above room temperature. Pyrophosphate is a polyvalent
anion with a high affinity for polyvalent cations, e.g. Ca2+.

Disodium pyrophosphate is produced by heating

sodium dihydrogen phosphate
:

2 NaH2PO4 → Na2H2P2O7 + H2O

Food uses

Disodium pyrophosphate is a popular leavening agent found in baking powders. It combines with sodium bicarbonate to release carbon dioxide:

Na2H2P2O7 + NaHCO3 → Na3HP2O7 + CO2 + H2O

It is available in a variety of grades that affect the speed of its action. Because the resulting phosphate residue has an off-taste, SAPP is usually used in very sweet cakes which mask the off-taste.[2]

Disodium pyrophosphate in baking powder, New Zealand, 1950s

Disodium pyrophosphate and other

darkening.[4]

Disodium pyrophosphate can leave a slightly bitter aftertaste in some products, but "the SAPP taste can be masked by using sufficient baking soda and by adding a source of calcium ions, sugar, or flavorings."[1]

Other uses

In leather treatment, it can be used to remove iron stains on hides during processing. It can stabilize hydrogen peroxide solutions against reduction. It can be used with sulfamic acid in some dairy applications for cleaning, especially to remove soapstone. When added to scalding water, it facilitates removal of hair and scurf in hog slaughter and feathers and scurf in poultry slaughter. In petroleum production, it can be used as a dispersant in oil well drilling muds.[citation needed] It is used in cat foods as a palatability additive.[6] Disodium pyrophosphate is used as a tartar control agent in toothpastes.

References

  1. ^ a b "Lallemand Baking Update: Chemical Leaveners Volume 1 / Number 12" (PDF). www.lallemand.com. Lallemand Inc. 1996. Retrieved 6 January 2018.
  2. doi:10.1002/0471238961.0308051303082114.a01.pub2
  3. ^ http://www.foodproductdesign.com/articles/1994/08/in-the-can.aspx -Retorting, Accessed 2010-11-27
  4. ^ a b Ellinger, R.H. (1972). "Phosphates in Food Processing". Handbook of Food Additives (2nd ed.). Cleveland: CRC Press. pp. 617–780.
  5. ^ "Food-Info.net : E-numbers : E450 Potassium and sodium di-phosphates".
  6. ^ Roach, Mary (2013-03-25). "The Chemistry of Kibble". Popular Science. Retrieved 2016-02-16. Pyrophosphates have been described to me as "cat crack." Coat some kibble with it, and the pet food manufacturer can make up for a whole host of gustatory shortcomings.

External links

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