1-Naphthalenesulfonic acid, 6-diazo-5,6-dihydro-5-oxo-, thiodi-4,1-phenylene ester 4,4'-Diphenolsulfide, bis(2-diazo-1-naphthol-5-sulfonate) 68901-24-6 EINECS 272-667-8 Thiodi-1,4-phenylene bis(6-diazo-5,6-dihydro-5-oxonaphthalene-1-sulphonate)