Disodium pyrophosphate

Disodium pyrophosphate
Names
	IUPAC name Disodium dihydrogen diphosphate
	Other names Diphosphoric acid, disodium salt; Disodium dihydrogen pyrophosphate; Disodium diphosphate; Sodium acid pyrophosphate
Identifiers
CAS Number	7758-16-9 ;
ECHA InfoCard	100.028.941
EC Number	231-835-0;
E number	E450(i) (thickeners, ...)
CompTox Dashboard (EPA)	DTXSID7044261 ;
Properties
Chemical formula	Na2H2P2O7
Molar mass	221.94 g/mol
Appearance	white odorless powder
Density	1.1-1.3 g/cm3
Melting point	>600 °C
Solubility in water	11.9 g / 100 ml (20 °C)
Hazards
Flash point	Non-flammable
Related compounds
Other anions	Disodium phosphate; Pentasodium triphosphate; Hexasodium metaphosphate
Other cations	Dipotassium pyrophosphate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Disodium pyrophosphate or sodium acid pyrophosphate is a buffering and chelating agent, with many food and industrial uses. It is polyvalent, and acts as a Lewis base, so is effective at binding polyvalent cations.

Food uses

Sodium acid pyrophosphate is a GRAS substance for food use. It is used in canned seafood to maintain color and reduce purge during retorting. It is an acid source for reaction with baking soda to leaven baked goods. In cured meats, it speeds the conversion of sodium nitrite to NO₂^- by forming the HONO intermediate, and can improve water holding capacity. Disodium pyrophosphate also is found in frozen hash browns and other potato products, where it is used to keep the color of the potatoes from darkening^[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 the 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.

References

^ Ellinger, R.H. (1972) Phosphates in Food Processing in Handbook of Food Additives, 2nd Ed., CRC Press, Cleveland, pp. 617-780.

[1] Ellinger, R.H. (1972) Phosphates in Food Processing in Handbook of Food Additives, 2nd Ed., CRC Press, Cleveland, pp. 617-780.

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