Benzidine yellow, structure

The role of structural Fe(III) In reactions with benzidine was also demonstrated by Mossbauer spectroscopy at very high adsorption levels (i.e., intercalation conditions) on montmorillonite (40). Upon dehydration of the clay, a yellow color and regeneration of Fe2+ to Fe3+ was observed. This was explained by the equilibria... 

Investigation into the structure of the sulfur-bake dye Immedial Yellow GG, Cl Sulfur Yellow 4 [1326-75-6] (Cl 53160), by chemical degradation of the dye and confirmatory synthesis of the postulated structures showed that a mixture of four dyes was obtained when benzidine and 4-(6-methjI-2-benzothiazolyl)aniline were baked with sulfur. The original British patent for Sulfur Yellow 4 dates back to 1906 (19). The principal structure obtained is (1). 

An example of a yellow sulfur dye is Immedial Supra Yellow GWL which may be prepared by thionation of a mixture of benzidine and dehydrothio-p-toluidine. Zerweek and coworkers suggested the structure consists of four dyes but a more recent degradative study indicates that the major component is (26) (62CCC1533). 

It is believed that the reactions indicated in equations (A) and (B) both play an important part in the formation of sulphur dyes. When a mixture of benzidine (NHg.CeHi.CeH. NHj) anddehydrothio-toluidine is heatedwith sulphur or sodium polysulphide a yellow sulphur dye known as Immedial Yellow GG is obtained. The dye is a disulphide, but degradation products have been isolated which show that it is built up from units of the structure... 

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