Title: Orthanilic Acid
CAS Registry Number: 88-21-1
CAS Name: 2-Aminobenzenesulfonic acid
Synonyms: o-sulfanilic acid;
o-anilinesulfonic acid
Molecular Formula: C6H7NO3S
Molecular Weight: 173.19
Percent Composition: C 41.61%, H 4.07%, N 8.09%, O 27.71%, S 18.51%
Literature References: Prepn from
o-nitrobenzenesulfonyl chloride: Wertheim,
Org. Synth. coll. vol. II, 271 (1943).
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.
pKa: pK (25°) 2.48