Pyrogallol

From Wikipedia, the free encyclopedia

This article does not cite any references or sources. (November 2007)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

Pyrogallol

Other names	1,2,3-Trihydroxybenzene Pyrogallic acid
Identifiers
CAS number	[87-66-1]
SMILES	OC1=C(O)C=CC=C1O
Properties
Molecular formula	C₆H₆O₃
Molar mass	126.11 g/mol
Density	1.45 g/cm³
Melting point	131-134 °C
Boiling point	309 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Pyrogallol or benzene-1,2,3-triol is a white crystalline powder and a powerful reducing agent. It was first prepared by Scheele 1786 by heating gallic acid. An alternate preparation is heating para-chlorophenoldisulphonic acid with potassium hydroxide.

When in alkaline solution, it absorbs water readily, turning purple from a colourless solution. It can also absorb oxygen and is used to calculate the amount of oxygen in air.

One can find its uses in hair dying, dying of suturing materials and for oxygen absorption in gas analysis. It also has antiseptic properties. Pyrogallol was also used as a developing agent in black-and-white developers, but its use is largely historical except for special purpose applications. (Hydroquinone is more commonly used today.)

Limited exposure to this compound is recommended. Pyrogallol is not likely to be used as a modern hair dye due to the suspected toxicity of the compound.

[edit] See also

[edit] References

This article does not cite any references or sources. (September 2007)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.