2-Naphthalenesulfonic acid, 1,4-dihydro-1,4-dioxo-, ammonium salt 56633-19-3 5690-16-4 Ammonium 1,4-dihydro-1,4-dioxonaphthalene-2-sulphonate Ammonium 1,4-naphthoquinone-2-sulfonate EINECS 260-296-4