1,4-Bis((3-carboxy-4-hydroxyphenyl)azo)benzene-2-sulfonic acid, trisodium salt 72230-95-6 Benzoic acid, 3,3'-((2-sulfo-1,4-phenylene)bis(azo))bis(6-hydroxy-,trisodium salt EINECS 276-501-5 Trisodium 5,5'-((2-sulphonato-1,4-phenylene)bis(azo))bis(salicylate)