1,3-Naphthalenedisulfonic acid, 7-((4-aminophenyl)azo)-, disodium salt 67893-49-6 7-(4-Aminophenylazo)-1,3-naphthalenedisulfonic acid, disodium salt Disodium 7-((4-aminophenyl)azo)naphthalene-1,3-disulphonate EINECS 267-624-5