Pyrophosphoric acid

Synonym(s):Diphosphoric acid

CAS NO.：2466-09-3
Empirical Formula: H4O7P2
Molecular Weight: 177.98
MDL number: MFCD00011343
EINECS: 219-574-0
SAFETY DATA SHEET (SDS)
Update Date: 2024-08-28 13:53:20

What is Pyrophosphoric acid?

Description

Pyrophosphoric acid, also known under the name diphosphoric acid, is colorless, odorless, hygroscopic and is soluble in water, diethyl ether and ethyl alcohol. It is produced from phosphoric acid by dehydration. Pyrophosphoric acid slowly hydrolyzes in the presence of water into phosphoric acid.
H4P2O7 +H2O?2H3PO4
Upon heating, phosphoric acid loses water, being converted successively, and to some extent concurrently, into the pyro- and meta-acids:
2H3PO4?H4P2O7 +H2O
nH3PO4?(HPO3)n + [H2O]n

Chemical properties

White to very pale yellow glassy solid

Physical properties

Colorless needles or liquid; hygroscopic. Crystallizes in two anhydrous forms: a metastable form melting at 54.3°C and a second and more stable form melting at 71.5°C; extremely soluble in cold water, reacting very slowly to form phosphoric acid; decomposing much faster in hot water; very soluble in alcohol and ether.

The Uses of Pyrophosphoric acid

Pyrophosphoric Acid has been shown to enhance the rate of pyrophosphate hydrolysis by nonenzymatic catlysis and by inorganic pyrophoshatase. Pyrophosphoric Acid can be used for the preparation of vanadyl pyrophosphato methoxide cluster anion. Pyrophosphoric Acid is used in anion binding of inorganic phosphates due to is ability to form complexes.

The Uses of Pyrophosphoric acid

Catalyst, manufacture of organic phosphate esters, metal treatment, stabilizer for organic per- oxides.

What are the applications of Application

Pyrophosphoric acid is An enhanger of the rate of pyrophosphate hydrolysis by nonenzymatic catlysis and by inorganic pyrophoshatase

Definition

ChEBI: An acyclic phosphorus acid anhydride obtained by condensation of two molecules of phosphoric acid.

Preparation

According to early investigators, the pyro-acid is formed as low as 100 °C, and the conversion is complete between 255 and 260 °C. Phosphorous oxychloride reacts with phosphoric acid in the following manner:
5H3PO4 + POC13?3H4P2O7 + 3HC1
A mixture of the ortho- and meta-acids may be condensed together to form the pyro-acid by heating on the water bath:
nH3PO4 +[HPO3]n?[H4P2O7]n

Metabolism

Not Available

Properties of Pyrophosphoric acid

Melting point:	61 °C
Density	approximate 1.9g/ml (25℃)
storage temp.	-20°C, Hygroscopic
solubility	DMSO (Soluble)
form	white crystals
pka	0.99±0.10(Predicted)
color	white crystals, crystalline
Water Solubility	709g/100mL H2O (23°C); soluble alcohol, ether [MER06]
Merck	13,8098
Stability:	Hygroscopic, Moisture Sensitive
CAS DataBase Reference	2466-09-3(CAS DataBase Reference)
EPA Substance Registry System	Diphosphoric acid (2466-09-3)

Safety information for Pyrophosphoric acid

Signal word	Danger
Pictogram(s)	Corrosion Corrosives GHS05 Exclamation Mark Irritant GHS07
GHS Hazard Statements	H302:Acute toxicity,oral H314:Skin corrosion/irritation
Precautionary Statement Codes	P280:Wear protective gloves/protective clothing/eye protection/face protection. P310:Immediately call a POISON CENTER or doctor/physician. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.