4,4,-dinitrostilbene-2,2,-disulfonic acid

The starting compound for all triazinylaminostilbenes is 4,4 -dinitrostilbene-2,2 -disulfonic acid [128-42-7], which is obtained by oxidizing 4-nitrotoluene-2-sulfonic acid with aqueous sodium hypochlorite in the presence of sodium hydroxide or, more recently, by atmospheric oxidation in an aqueous ammoniacal medium [39], The Bechamps reduction using iron filings etched with hydrochloric acid yields 4,4 -diaminostilbene-2,2 -disulfonic acid [81-11-8] (DAS). 

Ethenediyl)bis(5-nitrobenzenesulfonic acid), di-sodium salt. Benzenesulfonic acid, 2,2 -(1,2-ethenediyl)bis(5-nitro-, disodium salt 4,4 -Dinitrostilbene-2,2 -disulfonic acid, disodium salt Disodium 4,4 -dinilro-2,2 -stilbene-disulfonic acid Disodium 4,4 -dinitro-2,2 -stilbene-disulfonate Disodium 4,4 -dinitrostilbene-2,2 -disulphon-ate EINECS 223-051-2 NSC 163175 2,2 -Stilbenedisulfonic acid, 4,4 -dlnltro-, disodium salt. 

Nitrotoluene is used mainly in the manufacture of pure 2,4-toluene diisocyanate. The second most important product is 4-nitrotoluene-2-sulfonic acid, obtained by sulfonation, which is converted into 4,4 -dinitrostilbene-2,2 -disulfonic acid (DNSDSA) by oxidation with sodium hypochlorite. The reduction of DNSDSA yields the corresponding amino-compound (DASDSA), which is used in the manufacture of optical brighteners and dyes. 

---