6882. Orthanilic Acid

Nomenclature

CAS number: 88-21-1
2-Aminobenzenesulfonic acid; o-sulfanilic acid; o-anilinesulfonic acid.
C6H7NO3S; mol wt 173.19.
C 41.61%, H 4.07%, N 8.09%, O 27.71%, S 18.51%.

Description and references

Prepn from o-nitrobenzenesulfonyl chloride: Wertheim, Org. Synth. coll. vol. II, 271 (1943).

Chemical structure

Properties

Minute hexagonal plates, dec ≈325°. Slow crystallization from water below 13.5° may yield a hemihydrate. pK (25°) 2.48. Slowly and sparingly sol in water.