1,6-Naphthalenedisulfonic acid, 4-amino- 1-Naphthylamine-4,7-disulfonic acid 4-Amino-1,6-naphthalenedisulfonic acid 4-Aminonaphthalene-1,6-disulphonic acid 85-75-6 Dahl's acid III EINECS 201-630-0 NSC 7557