1,3-Naphthalenedisulfonic acid, 7,7'-(carbonylbis(imino(5-methoxy-2-methyl-4,1-phenylene)azo))bis-, tetrasodium salt 12217-64-0 7,7'-(Ureylenebis((5-methoxy-2-methyl-p-phenylene)azo))di-1,3-naphthalenedisulfonic acid, tetrasodium salt 74398-76-8 EINECS 235-400-6 Tetrasodium 7,7'-(carbonylbis(imino(5-methoxy-2-methyl-4,1-phenylene)azo))bis(naphthalene-1,3-disulphonate)