Пирофосфат натрия

Описание

Sodium acid pyrophosphate (SAPP), or disodium pyrophosphate, is a condensed phosphate formed when sodium orthophosphate is heated to remove the water. It is an inorganic compound consisting of sodium cations and pyrophosphate anion. It is used in food mainly for its two properties: It is a leavening acid that combines with baking soda to release carbon dioxide to improve the texture and volume of baked goods. It is a chelating agent to chelate iron to prevent discolouration in processed potatoes. It is extensively used in food processing, such as in canned seafood, cured meat, and potato products, to adjust the pH, maintain colour, improve the water-holding capacity, and reduce purge during retorting. However, little is known about its toxicity[1].

Химические свойства

Disodium dihydrogendiphosphate [7758-16-9], disodium diphosphate, acidic sodium pyrophosphate, Na2H2P2O7, Mr 221.97, d 2.31. Its solubility in water is 13g Na2H2P2O7/100g H2O at 20 °C, and 20g at 80°C. The pH of a 1% aqueous solution is 4.1. The usual commercial product is the anhydrous, nonhygroscopic salt in powder form. The hexahydrate, Na2H2P2O7.6H2O, d 1.85, crystallizes from aqueous solution below 27 °C. Above this temperature, it is converted to the anhydrous form. Disodium diphosphate is used as a (tropically stable) acid carrier in baking powder, for improvement of flow properties in flour, for pH regulation, and in dental care products for prevention of tartar formation.

Подготовка

Disodium dihydrogendiphosphate is produced from sodium dihydrogenmonophosphate by heating at 200-250℃：
Na2CO3+2H3PO4→2NaH2PO4+H2O+CO2↑
2NaH2PO4→Na2H2P2O7+H2O

Общее описание

The APP (amyloid precursor protein) gene is mapped to human chromosome 21q21.3. It encodes a integral membrane protein. APPα is a soluble protein generated by sequential cleavage with α and γ secretase.

Профиль безопасности

Poison by intravenous route. Moderately toxic by ingestion and subcutaneous routes. An irritant to skin, eyes, and mucous membranes. When heated to decomposition it emits toxic fumes of POx, and Na2O.