2-Naphthalenesulfonic acid, 6,6'-(carbonylbis(imino(1-hydroxy-6,2-naphthalenediyl)azo))bis- 2-Naphthalenesulfonic acid, 6,6'-ureylenebis((1-hydroxy-6,2-naphthalenediyl)azo)di- 6,6'-(Carbonylbis(imino(1-hydroxynaphthalene-2,6-diyl)azo))bisnaphthalene-2-sulphonic acid 65000-34-2 EINECS 265-305-5