1,3-Naphthalenedisulfonic acid, 7,7'-((4,6-dihydroxy-1,3-phenylene)bis(azo))bis- 65151-32-8 7,7'-((4,6-Dihydroxy-1,3-phenylene)bis(azo))bisnaphthalene-1,3-disulphonic acid EINECS 265-531-4