Modification of a vinylsulphone reactive dye using diethanolamine-O-disulphate

The β-sulphatoethylsulphone dye, Remazol Orange 3R, was converted to its vinylsulphone form and then reacted with diethanolamine- O -disulphate (DES) to produce a new type of reactive dye carrying pendent amino-di(ethyl- O -sulphate) groups. Application of the latter dye to cotton, using the pad–dry–steam process in the presence of alkali, resulted in a good level of dye–fibre covalent fixation. It had been expected that the sulphate ester would react by nucleophilic substitution to give bifunctional covalent attachment of the dye to cotton. It was shown, however, that an intermediate dye containing an aziridine residue was produced, which under hot alkaline conditions was converted by β-elimination to the vinylsulphone dye, and it was in this form that reaction with cotton took place.