2-Naphthalenesulfonic acid, 5(or 8)-((3-methyl-4-(((4-methylphenyl)sulfonyl)oxy)phenyl)azo)-8(or 5)-((4-((4-nitro-2-sulfophenyl)amino)phenyl)azo)-, disodium salt 73681-17-1 8003-88-1 C.I. Acid Orange 51 Disodium 5(or 8)-(3-methyl-4-(4-methylphenylsulphonyloxy)phenylazo)-8(or 5)-(4-(4-nitro-2-sulphophenylamino)phenylazo)naphthalene-2-sulphonate EINECS 232-328-7