104-23-4 4'-Aminoazobenzene-4-sulfonic acid 4'-Sulfo-4-aminoazobenzene 4-Aminoazobenzene-4'-sulfonic acid Aminoazobenzenesulfonic acid Benzenesulfonic acid, 4-[(4-aminophenyl)azo]- C.I. 13011 (Free acid) C.I. Food Yellow 6 NSC4704 p-[(p-Aminophenyl)azo]benzenesulfonic acid