Disodium pyrophosphate

• E 450a
• E 450 ( i)
• Disodium dihydrogen pyrophosphate
• Dibasic sodium pyrophosphate

Colorless and odorless powder

Fixed

1.86 g · cm -3

220 ° C ( decomposition)

Moderately in water ( 120 g · l-1 at 20 ° C)

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Disodium dihydrogen Na2H2P2O7, a sodium salt of pyrophosphoric acid, belongs to the group of diphosphates. It is used as a food additive, among others, and often incorrectly referred to as disodium diphosphate.

Preparation and Properties

Na2H2P2O7 can be prepared from sodium dihydrogen phosphate by heating to about 245 ° C.

Or by reacting the diphosphonic acid with two equivalents of sodium hydroxide solution.

The salt is readily soluble in water and slightly acidic.

Use

In food chemistry Na2H2P2O7 is used under the name E 450a as an additive for baking powder; because it is acidic, it promotes the decomposition of the leavening agent. Because as pyrophosphate has the tendency to absorb water from its surroundings and this regress the above sodium

It is also used as dehydrating a food preservative.

Swell

• Arnold F. Holleman, Nils Wiberg: Textbook of Inorganic Chemistry, 102 Edition, de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1.

• Phosphate
• Sodium compound
• Food additive