Sulfanilic acid
IUPAC name	p-aminobenzenesulphonic acid
Other names	Sulphanilic acid
Identifiers
CAS number	121-57-3 Y
PubChem	8479
SMILES	C1=CC(=CC=C1N)S(=O)(=O)O
InChI	InChI=1/C6H7NO3S/c7-5- 1-3-6(4-2-5)11(8,9)10/h1-4H, 7H2,(H,8,9,10)/f/h8H
Properties
Molecular formula	C6H7NO3S
Molar mass	173.19
Melting point	288 °C, 561 K, 550 °F
Solubility in water	>20 g/l
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sulfanilic acid (4-aminobenzene sulfonic acid ) is a colourless crystalline solid produced from sulfonation of aniline.^[1]

It readily forms diazo compounds and is used to make dyes and sulpha drugs. ^[1]

Sulphanilic acid exists as a zwitterion, and has an unusually high melting point.

[edit] References

1. ^ ^{a b} "Sulphanilic acid". A Dictionary of Chemistry. Oxford University Press, 2000. Oxford Reference Online. Oxford University Press.