2606-93-1 Amar White RWS Benzensulfonic acid, 2,2'-(1,2-ethenediyl)bis(5-(((phenylamino)carbonyl)amino)-, disodium salt Blancophor R Disodium 4,4'-bis(3-phenylureido)stilbene-2,2'-disulphonate EINECS 220-021-0