72252-60-9 Benzenesulfonic acid, 2,2'-((1,4-dioxo-2-butene-1,4-diyl)bis(imino(2-methyl-4,1-phenylene)azo))bis(5-((4-sulfophenyl)azo)-, tetrasodium salt EINECS 276-540-8 Tetrasodium 2,2'-((1,4-dioxo-2-butene-1,4-diyl)bis(imino(2-methyl-4,1-phenylene)azo))bis(5-((4-sulphonatophenyl)azo)benzenesulphonate)