1,3-Naphthalenedisulfonic acid, 6-((4-((4-ethoxyphenyl)azo)phenyl)azo)-, disodium salt 67875-17-6 Disodium 6-((4-((4-ethoxyphenyl)azo)phenyl)azo)naphthalene-1,3-disulphonate EINECS 267-532-5