| Disodium pyrophosphate | |
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Disodium dihydrogen diphosphate |
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Other names
Diphosphoric acid, disodium salt |
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| Identifiers | |
| CAS number | 7758-16-9 |
| PubChem | 9837369 |
| ChemSpider | 8013090 |
| UNII | H5WVD9LZUD |
| EC number | 231-835-0 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular 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 | |
| EU Index | Not listed |
| Flash point | Non-flammable |
| Related compounds | |
| Other anions | Disodium phosphate Pentasodium triphosphate Hexasodium metaphosphate |
| Other cations | Dipotassium pyrophosphate |
| Related compounds | Tetrasodium pyrophosphate |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| 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.
Sodium acid pyrophosphate is a GRAS substance for food use. It is used in canned seafood to maintain color and reduce purge during retorting. Retorting achieves microbial stability with heat[1]. It is an acid source for reaction with baking soda to leaven baked goods.[2] 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.[2]
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.